SAPMAN,
In regard to your first question, that is the big question that many of us elite FF's are waiting for. So far, there is no answer to that question. From what I've read, though, the 'experts' seem to think that we will garner the same benefits once the codeshare is implemented. I, for one, will be pretty pissed off if the new deal doesn't earn me credit towards elite status if I choose to fly Am West. I'd be no more inclined to use them than any other airline.
As to the $1,500 promo that's being offered by TWA, I would find it very unlikely that the promo would apply to AWA flights. This was offered solely by TWA prior to any codeshare announcement being made, and AWA certainly had nothing to do with it.