I have built many resin models.

Yes, CA is the only glue you can use. I use CA, plus CA accelerator, to fill air bubbles. You have to sand IMMEDIATELY, or the CA will become harder than the surrounding resin and will be nearly impossible to sand without damaging the surrounding area.

As for painting, I clean resin thoroughly with soapy water before painting. Then I use my usual paints - Krylon primer, Rustoleum, Testors, etc. Just follow the normal "rules" for mixing and matching paints (to avoid "raisin skin" effect).