Assuming you have a picnic, yeah remove the skin and fat (although I've seen it left on but IMO take it off). No one will want to (or be able to ) eat it. Butt won't have any skin or fat like the picnic does.
I remove the fat cap and other easily accessible globs.
There's more than enough fat throughout the meat to keep it juicy. The big chunks will be coming off one way or the other- either before smoking or when you pull it.