I think the problem with that, apart from any game mechanics difficulties, is that assuming you could unsummon one or more you would be resummoning 3 or 4 or however many the skill tree allows so you’re always going to have some that aren’t what your looking for. Plus there’s no guarantee that the one/s you want will stay on a resummons since you would have an odd number to the max allowed and you can’t pick which ones won’t disappear.
Better to max out the skill tree completely since that gives you better skellies all round no matter what type they are.