I really like the first remake, the Code: Veronica and Revelations. I think Revelations did a pretty good job of adaptating the new gameplay with elements of the older ones.
You have lots of backtracking, enemies without drops, limited items, and I remember when we have to run from two of those chainsaw-like monster my heart was beating very fast. Hahaha
Sorry, I didn't see your reply!

Do P2 and P3 give anything good? I got P1 because of the cooldown, if both of these just have the banner and some threads on VIP section I think I'll gather coins to go directly for P4.
Regarding RE: Since the games have lots of different genres/gameplays, I suggest playing at least one of each to see how you like them.
Whenever I'm playing a new series, I usually start from the first one released or, if they have it, their remake, so I'd start from the fisrt remake. But I think the order doesn't matter. Just play it, they're good!
But also I didn't get what you meant at your last paragraph, about first player or second. I don't know the mod scene from these games, but I think they have at least visual mods (custom skins). Resident Evil 4 remake for example, has some sexy ones. Hahaha