Not super familiar with the Farsight expansion, but in general terms this list looks workable, if a tidbit risky.
Basically you're fielding a 750 point army with 25-ish wounds, most of which are on instakillable Marine-save platforms. An army sporting a handful of lascannons/missile launchers is going to have themselves a turkey shoot (assuming, of course, they're smart enough to not bother shooting the Riptide). Were I you, I'd start everything on the board rather than leaving stuff hanging back in reserve.
If I start a game against this list and find myself facing a (1) Riptide, (2) Crisis Suits, (3) Pathfinders, and (4) Broadsides, all I'd do is aim my anti-infantry at the Pathfinders (and they'll die) and my antitank at the Crisis suits (and they'll die) and I'm one dead troops choice away from winning/drawing most objective games. Then again, terrain, deployment and the army I'm bringing may make it so I can't quite do that. I can think of lots of situations where it's very possible, though. Throwing the second group of suits on the board to start at least makes target priority more difficult for your opponent *and* guarantees they'll be contributing to offense on turn one, which is essential for a low-numbers list like this.
Oh, and simply accept that the Pathfinders will shoot once (maybe twice) and then die. It is almost guaranteed; Pathfinders are too dangerous and too easy to kill to let live, which is why I just don't take them anymore. I get more mileage from Marker Drones, Tetras, and Skyrays.
Final note: the Riptide should probably get an Ion Accelerator and a Early Warning Override with Smart missiles as the secondary. Cheap, effective, and very useful.