1. As far as Cece is concerned, once you've exhausted dialogue with her, her questline is done until later in Rika's.
2. So a problem with version 4.1 is that in version 3.2 you could go visit Rika once a night to shag once you had exhausted all of her questline, but since they added on to Rika's questline, my guess is they had to do away with that option or forgot to put it back in. Once you get that lock of hair, it will continue the questline.
3. Just keep checking back with her, asking for the hair, and complementing her when she comes to collect. She should eventually give it up.
4. Honestly, aside from expanding the barn, buying gold, monsters, or for stuff in the questline, you really don't need much. You can't get any other buildings upgraded in 4.1 and you can't visit the queen. You can 'tumble' with Eros and Cece after you've exhausted Rika's questline though. Cece will come to you, and you just have to visit Eros with at least 200 energy left after you've dealt with Cece.
5. Can't really say who to talk to about that. The developers have all but abandoned there postings of the project here. Everything is now handled through their Patreon, so my only guess is you'll have to pay a dollar at least to get on their message boards or discords.
I've gotten perfect breeds in almost every type of monster, and I still enjoy messing with this game and finding new aspects to it. It's fun and has a lot of potential.