Hello Spine community!

So, I've finally been able to get Spine Pro, which I'm hoping is going to make things exponentially easier to make the animations I want for my Unity games.
That being said, when it comes to skeletal animations, I'm still very new. Thankfully, looks like there's a lot of amazing resources out there so far, which is nice.
My questions here mostly stem from making sure / trying to understand if I'm approaching all this stuff and thinking about this correctly. Also making sure I can actually do what I want lol.

It looks like I can hot-swap different image parts during animation and keep meshes and deformations, right? Ex. Unity doesn't allow sprite swapping for a part of a rig if an image was given a weighted mesh. I'm hoping that's not a big issue for Spine.

My main questions are: Is it smart to essentially draw, rig, AND animate a mannequin first, and once all of that is finished, then implement the actual art assets to be used? Could I copy one rig and animation set over entirely to a different asset fairly easily? Let's say I animate the mannequin's chest to make it look like it's breathing. Would I be able to swap that chunk for something else while keeping those weights, meshes, etc.? If I go this route with the mannequin, should I still have placeholders for all the peripherals I want to eventually animate? For example, If I rig and animate this mannequin without hair, Would it be difficult / time consuming to add / modify the rig and animation to have hair later when I add the "true" assets?

I'm asking these questions because I still can't easily determine what is the fastest and easiest way to make my character animations. I can't tell if it's better to make the full static art asset I would be using in-game and focus on this part of the process after I finish the art asset, OR, make the general-ish mannequin without any of the fancy details, focus on getting that rigged, get all the animations done for a character, then go back to make the "true" art assets, so that way I can plug and chug everything fairly quickly. It'll also let me know exactly what assets I'd need, for example, knowing what and how many hand assets I'm swapping during animations. I guess the thing I worry about is if I rig a mannequin, animate it exactly the way I want, and then I find out that when I try to add the true assets, things break or Spine doesn't allow me to do something that ends up doubling the amount of work I need to do. I'm working on a turn-based RPG, and there are uhhh a lot of animations to get done lmao.

Any tips and tricks would help! I wanna know what the pros do and how others approach stuff like this!