B-LFB is one of the ex-SQ planes (ANA ones are B-LFC and soon B-LFD)
Yes, you will only find it out on the day of travel... that is they block off the first three rows of seats. Regardless if you do online check-in, you can find it out. For the ex-SQ, the first three rows are 18, 19, and 20.
For my day of travel, J is actually pretty full but the main deck is pretty open...Not sure about the exact number... I will say 80%.
For the value, O8 is not a bad choice...
Carfield