Question [Q] HTC One AT&T unlocked on JB 4.1.2 , Mode of Action [Order of Mods]?

Hi ,

I just got a HTC One AT&T unlocked on JB 4.1.2 , I want to

1.Upgrade to latest JB
2.Root
3.s-off
4.custom bootloader with this phone .

But since the phone is unlocked it wont get OTA updates from AT&T so in what order should i attempt the mods . Will this require flashing full RUU from HTC ?