I would go ahead and get yourself up to speed on that so you know how this proposal would slot in over all. Same for Yautja, since clans and ranks already exist. Not sure what the changes to them would accomplish.
Yautja are there to spice up the round, not to act as an objective unto themselves. Giving the Marines a consistent mechanical reason to kill them would do away with any roleplay potential.
And abominations are statted toward fighting Marines anyhow since they have to build up stacks by scoring kills in order to get strong – they wouldn’t be the force multiplier I think you’re assuming they’d be.