First off, you're wasting a good amount of points in this list on stuff that you either shouldn't need or shouldn't use. To run unit by unit:
[HQ] - Commander & Crisis Bodyguard: 293 Points
Commander; Twin-Linked Plasma Rifle; Twin-Linked Missile Pod; 2 Shield Drones
Crisis Bodyguard; Plasma Rifle; Missile Pod; Vectored Retro-Thrusters
Crisis Bodyguard; Cyclic Ion Blaster; Missile Pod; Stimulant Injector
Provide support where needed; use S6/7 firepower for anti-infantry or anti-light vehicle duties
Twin-linking a commander's weapons gives very minimal returns, given his high BS. If you're taking Vectored Retro-Thrusters for this unit (which, by the way, I doubt you'll use very often and probably don't need), it would probably be better on the Commander (as he can split off and use it as well as use it with the unit). Additionally, this unit would benefit a lot from the Puretide Engram. Tank-hunters confers to the entire unit, and if these guys are going to be shooting Rhinos or Chimera or whatever, that will benefit this unit a lot. Lastly, I don't think the Stim Injector is really worth it, particularly not on a bodyguard.
Final point: why Bodyguards? You have a free elites slot, just use it. Save yourself a lot of points. There isn't much here that Bodyguards can do that a couple regular suits can't. With the savings from dropping the Stims, the twinlinking, and the Vectored, I've saved you enough points to buy a lot of other stuff that will be more useful, like additional FWs, the aforementioned Puretide Engram, or the like.
[TROOPS] - Fire Warrior Team: 79 Points
Shas'ui; Markerlight and Target Lock
5 Fire Warriors
Hold deployment zone objectives; apply markerlight
[TROOPS] - Fire Warrior Team: 79 Points
Shas'ui; Markerlight and Target Lock
5 Fire Warriors
Hold deployment zone objectives; apply markerlight
These guys won't be 'holding' much of anything if hit hard. They will fold in assault very quickly and aren't super durable against shooting, either. Your best option is to keep their target priority low by threatening the enemy with bigger problems. I, personally, am not crazy about the micro FW strategy. I'd rather see these two combined into one unit. In order to make MSU Tau work (and I don't think it works super well), you need four or five such units as this.
[TROOPS] - Kroot Carnivore Squad: 89 Points
14 Kroot
Kroot Hound
Outflank; attempt to take objectives
These are okay. I don't think you need the extra four bodies. Better to trade them in for a Krootox, which grants you almost as many wounds for greater range and firepower. These guys can't assault worth a damn except against Guardsmen, and even then it's dicey.
[TROOPS] - Fire Warrior Team: 170 Points
10 Fire Warriors
Devilfish
Form nucleus of deployment zone firebase; move to take objectives as necessary
Good unit. I'm usually a proponent of using Firewarriors aggressively, which is much of the reason to buy a Devilfish (ideally with a Disruption Pod). To do that well, however, you really need two units to operate in a pair. Since your points are short, however, and you're already building towards a static list, I'd say ditch the Devilfish and take another 8-9 firewarriors. New rapid fire rules mean you can fire just fine on the move, and that should be sufficient to take objectives. It also will draw firepower away from your smaller FW squads.
[ELITES] - XV8 Crisis Team: 208 Points
Shas'vre; Twin-Linked Plasma Rifle; Fusion Blaster; Shield Drone; Bonding Knife
Shas'ui; Plasma Rifle; Fusion Blaster; Vectored Retro-Thrusters; Shield Drone; Bonding Knife
Shas'ui; Twin-Linked Plasma Rifle; Fusion Blaster; Bonding Knife
Bulk of anti-MEQ/TEQ and anti-armor duties
Ditch the Vectored again--they won't come up often enough to matter. One shield drone should do. The bonding knives are pretty much useless. There is no good reason to take a Shas'vre here--your leadership will be good enough at the basic level, and that extra attack the shas'vre is toting is pointless. With the point savings, I'd recommend twinlinking Fusion Blasters where possible. The single anti-tank shot is more important to get that hit than the plasma shots, I've found.
[ELITES] - Stealth Team: 180 Points
Shas'vre; Homing Beacon; Bonding Knife
Shas'ui; Vectored Retro-Thrusters; Bonding Knife
3 Shas'ui; Bonding Knives
Infiltrate to allow accurate Crisis deep strike (if desired); provide anti-infantry support
Solid unit. Again, Bonding knives are a waste and I'm skeptical of Vectored Retro-Thrusters. VRT implies you are charging enemies (usually a bad idea) or surviving a round of combat (dubious). The points are better spent elsewhere.
[FAST ATTACK] - Pathfinder Team: 55 Points
5 Pathfinders
Markerlight allocation
Okay. I'd expect them to die pretty quickly against experienced opponents, since they are fragile and dangerous (this is an unavoidable issue with Pathfinders, though). Be sure to deploy them in spots where they are hard to reach, but also where they can get good support to the rest of the army. It's a tricky business.
[HEAVY SUPPORT] - XV88 Broadside Team: 97 Points
Broadside; Twin-Linked High Yield Missile Pod; Drone Controller; 2 Missile Drones
Stay near Fire Warriors; provide massed S7 firepower
Very good buy for a small game like this. Should pay off.
Notes:
The basic concept I had for this army was to avoid enemy assaults through outmaneuvering and careful clustering of several small complementary units (I toyed with going MSU
not sure how that works in 6th/with Tau). I'd likely deploy a firebase of fire warriors and the broadside to hold objectives in my own deployment zone, while I would infiltrate the stealth suits, advance the pathfinders, and either deep strike my crisis teams or leave them to support my fire warriors unit in the devilfish to deny/capture opponent's objectives. I would likely outflank with the kroot to challenge/capture midfield objectives as necessary.
A couple things about this plan: I don't think firewarriors should just sit on their butts and hope. Move them and plan on moving them. Leaving one team with the broadside is fine (they can support each other), but I've never had luck with static Tau and I've never seen anyone else have much luck with them, either. If you are devoted to dropping down a bunch of firewarriors to sit there and take the pain, you really ought to get yourself an Ethereal or Cadre Fireblade for support. They are cheap supporting HQs (which you could easily afford by dropping a few VTRs and such) and add a lot to a gunline firebase.
Pathfinders should *not* advance. If anything, they should attempt to stay at the maximum range they can while retaining effectiveness. Pathfinders are a very high target priority, in that they are both dangerous and very easy to kill. Any opponent with experience against Tau are going to blow them up immediately with a bare minimum of investment on their part. The closer they get, the easier it is to kill them. Rhino stormbolters can do significant damage to them, just to give you an idea of how little resiliency the unit has and how easy it can be for opponents to take them down.
The Stealth Teams and Crisis teams should work. Keeping at least one Crisis team starting on the board is recommended, just to get that firepower early on. Don't overestimate the effectiveness of Kroot--they die to a stiff breeze and aren't great on offense. Their best ability is to be annoying and not worth bothering to kill, all while sitting on some out-of-the-way objective.
Questions:
1) Do fire warriors work in both of these configurations? It seems there's no strong preference for how to field them; is this correct?
'Correct' is a strong word. There are two things important to note about Firewarriors: Poor leadership and good shooting en masse. Generally you want to have larger units, as they last longer and work better. That said, if you have a *lot* of small units, they can last simply because the enemy has to target each one separately. I don't think two small units will work as well as one large one. I think if you could get yourself 3 8-10 man firewarrior teams, you should be okay.
2) I'm lacking some high-AV tackling power, but I would ideally like to avoid a riptide, and I'm preferential to a Broadside over a Hammerhead. Are the Fusion Blasters on the Crisis team enough? Or should I consider Piranas with Fusion Blasters? I'm stumped on this one.
In a 1250 point match, you shouldn't see a hell of a lot of AV14, so the crisis team might be enough. Conventionally, if this were a 1500 or 1750 point match, I'd say 'no way'. I am a big fan of Piranhas with Fusions, but not really because they kill tanks that often. They are great for diverting firepower and delivering lots of gun drones to awkward places and then, also, occasionally they kill a tank before they die. I don't think your list is set up to capitalize upon them. What you have should serve for the size games you're playing. If you are going to start playing larger games, I'd say you need to seriously consider either (1) more Suits w/Fusion, (2) at least 4 Fusion Piranha, or (3) a Hammerhead.
3) Would it be worth trading one stealth suit for 2 more pathfinders and a seeker missile on the broadside? It would give me a couple more markerlights and some long-ranged anti-tank at the cost of a less-durable stealth suit team.
No. 100% no. Seeker Missiles work okay in salvos (i.e. skyrays), but a single one won't make any damned difference. Two more pathfinders would be better as *three* additional Pathfinders which would be then split into two teams of four. Two teams of four will last much, much longer than one team of 5-7.
Thank you so much for your feedback!
You're welcome! I hope I was helpful!