Exciting! Some thoughts on Forms:
Midnight Sorrow - seems premium tier. combined with Flip Belt and the alright high mobility, amazing for getting into contact with lots of enemies who would prefer not to have to Fall Back in the next turn.
Veiled Path - Interestingly, more useful the better your opponent's WS is, since it's more likely to result in something that will be useful. After all, if you're fighting an opponent with 5+ Weapon Skill, it's pretty unlikely for this to be useful, whereas an opponent with 2+ Weapon Skill is pretty likely to get blocked. With "2d6, choose lowest" the odds of results are
(table):
1 - 11/36
2 - 9/36
3 - 7/36
4 - 5/36
5 - 3/36
6 - 1/36
odds of this affecting a unit with WS5+: 4/36, 11% of the time
odds of this affecting a unit with WS4+: 9/36, 25% of the time
odds of this affecting a unit with WS3+: 16/36, 44% of the time
When successful, against enemies with a WS of 5+, it halves their damage output; against enemies with units of WS4+, it reduces their damage by 1/3rd; against enemies with WS of 3+, it reduces their damage by 1/4.
Generally speaking, expect this to either unreliably reduce enemy damage a significant amount (against inaccurate enemies with many attacks, for example), or to semi-reliably reduce enemy damage by a modest amount (against space marines, for example).
I'd consider this decent-tier, as it makes harlies more survivable in assault but I think a lot of armies are just going to Fall Back and shoot anyways rather than stay stuck in past the first combat.
Frozen Stars - just a straight-up large damage boost for your Players. If reaching tagging more enemies in assault and surviving fight phases aren't something you are having trouble with, this boost is hugely better than the previous two. Won't help during your enemy's fight phase, but easily premium tier anyway since you can reliably get the charge.
Soaring Spite - good for drive-bys, but doesn't seem to match up. Perhaps other changes that are coming will make this worth it. Unclear.
Dreaming Shadow - The Morale part seems nice but not particularly valuable given typical Troupe sizes. The final strike bit is nice in combat, but pretty avoidable for enemies if they're shooting at you. Staying out of Fusion PIstol range isn't hard, and a Shuriken PIstol shot is good, but not amazing. Mid-tier.
Silent Shroud - I play against many enemies with the ability to ignore morale, and morale bombs for Harlies don't seem as good as simply chopping the enemy to bits. Seems very good at what it sets out to do, but it's not clear to me that what it sets out to do is viable. Low-tier.