You need to start from scratch, you say you updated to Kit Kat after unrooting?? The reason why your phone isn't working properly is your update didn't complete properly. You have mismatches in your software version and baseband. Did you update with the OTA file or did you install one of the semi custom roms from the development section. Anyway, the wifi problem is probably a mismatch between your baseband and your kernel. Sense your software is NAE and your baseband is MK2 I don't know which hotspot you should use. Straighten out your install first and then you should have working wifi and hotspot.
Phones & Tablets: Galaxy S4, Galaxy Note 8", Evo 4g LTE, Evo 3D, Acer Iconia A500, Samsung Galaxy Tab 2 10.1, Ipad 2, Nabi 2,
Rom: Rooted Stock Odexed, Hotspot Mod, Xposed, Wanum, several other xposed tweaks