I'll answer your question in two parts.

Yes, water curing would allow you to foliar feed, HOWEVER, during the flower stages, foliar feed PROMOTES mold as well as insects. So its not generally a great idea.

Yes, you can use pesticides and your mold preventatives, but.... Would you really want to smoke that? No matter the cure, you know whats gone into it, do you want to risk hurting yourself, or anyone else? Unless your using RO'd water and doing a 14 day water cure, you can't be sure you get it all out.

Good luck! (I water cure)