(a) I wouldn't personally, I've not been through it myself, but seemingly it's the easiest thing to do yourself so unless you have complicated circumstances I can't see why you would.
(b) Why? How are they relevant to you?
(c) Why do you think it is? It's telling you you're not eligible *now*, which is correct.
(e) potentially but it'll just be some extra checks (which may mean there's a bit of a delay, not sure I'd call it 'abnormal' though personally)
Good luck.