Default NC2 on Dev model Qs

Greetings,

I have a Developer Note 3, and I upgraded to the NC2 leak and I have a couple of questions:

1. I am having random reboots, and I hear the lean kernel can be the issue. Can I just re-flash hashcode's in Odin over the top?
2. I also cannot set a PIN code lock, even after changing build.prop - Is there something else I can do to enable a lock?
3. Is there an advantage to the radio with NC4? Is that modem file available separately? Can I flash it without locking my phone to retail?

Thanks!

-R