The essentials, from what we know so far!

See I'm not so sure, I mean I get that you're pretty likely to use at least one of every model at some point, but I don't think that means that EVERY model is gonna be used as much as others. Like I don't think the Rocketmen (burning out their fuse out here alone) boat is gonna be needed for every list. I'd argue that they'll probably be more niche. Same feel could be said about some of the light jacks. True, you'll get use out of all of them, but unless you're running the CG infantry, the Retaliator is probably not going to be as effective.

Contrary to this, I feel that Doctor Morley is going to be an auto include if you're running Magnum Opus. Allyce is gonna be Auto, or at least highly utilized, in most lists simply because the minus 1 cost on spells (could be wrong their just my opinion).

So more in the spirit that I think OP intended, I imagine that a least one Toro and maybe Alyce or the Alchemists would be pretty safe early buys. I can't imagine that you could play CG and not want one or more Toros at some point.

You think they will remain essential? At the surface, yes id say the DBR is made to be essential, and the rust debuff to compensate if you are up against jacks seems like a no-brainer. I think it will be interesting to explore more refined lists though where you leave those pieces behind. Support is always good on paper, but even if you take the options for free that means you are NOT taking other options for free. Especially the suppressor seems to be bad enough when you do not need the Rust debuff that you could safely leave it at home and get a Toro instead. That dude will do actual damage against beasts and jacks alike. I figured that optmized and refined lists would have to be forged over months and months of playing to find the sweet spot. "Bring all the support" is something we all thought to try, but "what support can i make do without?" is a way harder question to answer