I believe the consensus on ACV rinses is you can do them as often as your hair can tolerate them. For me, it's about once a month. I realized that was the best frequency for me because when I did them too often, my hair stopped looking so good after doing it. The first few times (more spaced out), my hair felt really nice, was less frizzy and more shiny. When I did them too often, my hair stayed frizzier and didn't feel as good. They say ACV rinses can be drying if you do them too often.

Personally, I didn't find ACV rinses helpful with oily scalp issues. But I would still definitely do them because of the other hair benefits.

I'm interested to see what other people say about your other questions; I've been wondering those things too.
I have fine, 2c hair with normal porosity (I think.... ).

Currently, I'm using Suave Naturals Tropical Coconut (co-wash), LVPNG (regular conditioner), Giovanni Direct Leave-In, and HETT (gel). Every now and then (once a week or so, whenever my hair needs it) I use GTTT shampoo. I've had good success with plopping and pixie curling, but my hair dries best if I shower and then sleep on it. My hair does NOT like honey.

I've been CG since June 29th, 2009.