1) I'm not sure which one's to suggest for more rp'ing aspect. Sorry.
2) You'll have a primary stat you'll want to invest your attribute points in. If you look at your class traits you'll see the stat you get bonuses for and that will be where you want to invest heavily in.
3) the conjurer is a pretty cool healer. To make the most of your character if you follow up to white mage you'll need arcanist to a minimum of lvl 15 and ideally you'll want to level up thaumartage to around 26 to gain the swiftcast skill. Being a healer will almost get you instant queue pops into dungeons. Each spellcaster brings a different flavor to their execution. Since each benefits from the other I'd suggest experimenting with all 3 and see which feels right for you first.

Welcome to Eorzea! Enjoy your adventure!