As for Roles, I get different answers depending on where I look. Fortunately, you can use all your unlocked and set roles starting from the beginning, regardless of what your level is set to. I use Protect, Swiftcast, Esuna, Lucid Dreaming, and Rescue. When I am doing endgame stuff and possibly in a static, I will probably switch Rescue out for Largesse, but tbh, I already have one healing boost I never remember to use. Protect is pretty much a given, though there's some debate on the subject. Swiftcast is mandatory, if only for instant-Ascends. Lucid Dreaming will give you mana, and reduces the threat you're like to pull. Esuna will cure most status ailments. There are some dungeons where it's useless, though. Why Rescue? Stupid tanks. Sometimes pulling to the wall is a BAD IDEA. Also useful to get someone out of AOE.

Anyway, sorry for what turned out to be a long couple of posts, but I wanted to touch on things other than sect, lol.