well, I model all my pieces separate at first (easier for unwrapping and fixing issues) then I combine them all together in the end as one mesh for skinning/rigging. You'll want it as one mesh so you can skin/rig it. I'm sure there's other ways of going about it, but that's the way I've always done it.
yesh, you can unwrap everything then sew it all back together later in your UV space. and yesh you want to be at a finalized state before you start unwrapping. You do some trial and error and find a way you like for your workflow. Alot of artists have different ways of going about completing work, im just sharing some of…