Hey Ricky, I've moved your thread to our all-things-root area for you.
I'll take a crack at a few of your questions and throw in a few other observations.
1. The current release of Android is 5.0.1, which you probably already know, so that should/would be your eventual upgrade target.
2. An OTA on your current set will NOT install since you have non-stock files (probably the install-recovery.sh file and the custom kernel) since an OTA validates/cross-checks that the files to be patched match expected stock versions (which your's will not).
3. You'll have to somehow get your current setup back to stock before you can take and successfully install an OTA (not 100% sure if this is why you aren't being prompted--I suspect not since I don't believe that kind of check is present anywhere is Android and it left to the OTA to do (I wonder if the flash of the custom kernel disabled your system update process (i.e., knowing that you're now non-stock)?).
Hopefully you took a Nandroid backup of your stock setup before you rooted and/or flashed the custom kernel. Otherwise you might be faced with flashing a factory image (which you could do with the 5.0.1 factory images), but that typically wipes your current apps and data [I believe you can do a non-wipe factory image install, but I've never done that so I'll have to let others that have or know about them to chime in].
Cheers!
