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1) you cannot pre-select seats on AF medium-haul unless you fly J or be Elite Plus. There is no PE on medium-haul flights, so you are seated in Y (you will likely be seated at the front of Y section).
2) you will arrive in 2E and connect indeed in 2F. You will go through immigration and security in CDG. Customs will be in BCN (but you will hardly notice it, not as formal as in the US). You don't have to claim bags in CDG, but only at your final destination. Immigration could be very crowded at that time but you should be fine in 1h45.