So this is a very light, simple game. And I think that's fine.
I'm sure you'd never want to Manually Trigger something (as written you'd roll a d6 and hope you score the number of a unit within 3"). The problem with Manual Trigger is two-fold, as the model that receives an extra action can do everything the original model could do.
I actually really like the triggering mechanic in general; the automatic one, anyway, even if it is very random and could lead to a runaway leader. But it does give a reason to Push a model.
I'm not sure you need a 2x2 board for this game. Since it seems your models all want to be within 3" of each other, movements are very small, and your attack distances are very short, you'll have a lot of unused space, and it's going to take a lot of movement to even reach the mid-point.
Speaking of unused space, I'd like to see more creative objectives. For one, your combat is terribly unexciting, though functional and simple, and I can't imagine sitting through a game rolling to hit until four models finally died. Once you were on top of each other you'd essentially be making dice rolls until one of you gave up the ghost or the game finally ended, without any real player input. The other objective is similarly uninspired but at least gives a reason to Push, if only on Turn 4. I really feel that this game, with Objectives that force a players to get into a different headspace, would elevate this simple design.
Finally, I don't think your special abilities are impactful enough. Or at all. They're very modest, and I feel they're so modest you'd be better off without them, for simplicity's sake. If the point is to differentiate what the model can do, then it would be best to increase their capabilities.