Android Pay & custom rom

So I have tripped KNOX already. I'm using TWRP, Xstrolite 2.3.
I've tried unchecking superSU root and retrying. I've tried using root cloaker.
Is there an easy way to not have the bootloader unlocked? Or is it once I flashed TWRP, its unlocked forever. :p

Has anyone else been able to successfully use Android Pay? Post your experience