(1) Definitely, I've got the first series but seeing it in Megazine size would be fantastic!!
(2) Again, damn good idea. I'm reading The Metabarons just now. Damn good artwork, reminds me of a kind of John Burns/Mark Harrison kind of thing. Reads quite strangely sometimes, but that's probably the translation that does that.
(3, 4) Haven't seen them before
(5) I've still to go back and read all of Hellboy, so I can't say. I'd rather see a longer run though, unlike Preacher, which seemed to end rather suddenly.
Battle etc reprints, I'd love to see that, but I think I'd rather see a graphic novel of them come out.