I find my answers
Well, i think i find my answers. Maybe it will help someone else.
1- If i flash 4.3 OTA i will have a locked
bootloader (forever or use safestrap)
2- To jailbreak, according to the version of my firmware i will use the corresponding Casual program from Adams casual thread
3- After jailbreaking, rooting, installing custom recovery i can flash any custom rom (directly in recovery
, not with odin
4- Depending on the custom rom i will need to update the firmware
Usefull threads are in Verizon Galaxy Note II Android Development section.