I think it's time to do AW. also I'm always spica first AW person.

healer-wise I'd live with iris + alissa + maybe a dorca (50cc50) until you get a fedora or better healer. also CR some silver healers.

dragon crystals...never heard of such a thing. but I'd spend DC on a CR1 spica and AW fairies. just carry on farming it during breaks.

AW will help you 3* X and G-tiers better, aside from having higher rarity units (or mincost silvers)

I save up rainbow fairies and use them when I find it's a good time to do so (saki 4/5 -> 5/5 after feeding azamis, spica 4/5 -> 5/5 after feeding laurens, and so on)