Two tickets, I think you meant two record locators.

Well... You are probably on a ba stock. In this case, when you pull your AA flight on AA.com it is the way :
- you get the AA flight and the flight before (even if there are 3 flights that day).
Like this month, I'm flying PEM-CUZ-LIM-MIA, the first flight doesn't show up. So yes, this is normal.

About this, did you mean you got one AA record locator for each way ? This would not surprise me.

About seating :
The general rule is
- you'll be able to choose your seats on AA.com for AA operated flight (aa.com will show you then 'real' AA flight #)
- you'll be able to choose your seats on ba.com for BA operated flight (don't know what ba.com will show you).
Non status : toll until checkin. At that time you'll be able able to choose your seat for free among what's left .
Aadvantage gold : toll until 7 days. Free from 7 days prior flight.
Plat and exec plat : free at anytime

And by the way, if there's more than 4 flights on your reservation, you do get another "ticket number" for each extra 4. Remember old real tickets