This ROM is rooted and should have no wifi issues. There are many ways to arrive at it, but it is quite possible to have a rooted Nabi with Gapps and working wifi. Most issues with Wifi are because people got out of sync with Nabi updates.
I think Jelly Bean is possible. I have tried compiling CM10(Jelly Bean 4.1.2) a few times but I have something wrong with audio and can't complete compile. Too busy lately to figure out where my device tree is wrong, some make file is wrong.