Congrats on finding what you like to do in this domain :)
They can all be centered in their respective boxes (maybe the exception of crouching legs, they'd need to be a bit higher to align with the torsos. (But I'd still call it centered))
The difference is that it's just one coordonate offset to program, so it's very easy to do
I ramble a lot so I had to rewrite this comment three times lmao.