Tidying up post-game... where are the best locations for Lumina, Chroma, and Exp?

[Talbot]

I've done just about everything there is to do (just that one mime left...) but I'm still seven levels short of 99, there are are a handful of Gestral merchants still sitting on a bunch of expensive Picto updates I can't afford, and there are so many more Lumina I want to shove onto people.

What're the best places to quickly grind towards each of those ends, and is there on spot that's a good compromise for grinding all three?