1. Yes, iOS 8 supports webgl. Andriod 5+ supports webgl 3 and Android 4+ supports webgl 2 (I believe)
2. Cocoon.io is a good option for android, most of us have been getting better performance out of it, but it also seems a few more set up issues can occur. When it works though, it's pretty awesome.
Intel XDK is good for iOS, fairly easy and painless too. I haven't tried cocoon.io for iOS yet, but it could be interesting.