Yes, you should still get the online booking bonus, a fare rollover does not make a difference there. (I think the booking bonus depends on whether the PNR was initially created through aa.com, whatever you change later does not matter as long as it's done within the same PNR).

If you have two people on one PNR, they will both get the booking bonus (assuming that PNR was created on aa.com), no need to separate the reservations.