Couple questions on shields & skills

I did search first, might have missed these. First, do skills gained only from a mod still count? Or do I need to have that tier of skill available before the mod bonus kicks in? Second, is it possible for legendary shields to get the +40% capacity bonus? More specifically, I’m wondering if the bonus can roll on the GenIVIV shield, which is bonus legendary & unique. Thus far, I have seen her shield with annointment, projector, and 1-2x absorbing & reflecting.

Class mod skills are always active, even if you did not unlock the skill yourself with a skill point. I do not know the answer about shields. I would love to have a legendary shield that has a lot of max health increases on it.