that’s OK. Regarding the a and e and N I have no idea what it is meaning. PHHusson has created this variants and I don’t know it.
TWRP you can forgot. You have your own working TWRP which will be OK.
Some devices do have this vbmeta partition for verified boot. If you will get an error while trying to flash, OK, forget that step.
Pls keep in mind, I can’t garantee that the GSI will work, So pls be prepared to go back to your latest version