Striker,
Yes, the highest level players, from alliance member clubs, would train with the highest level players from the area, and play for Bridge FA. To say that Bridge FA will or will not have premier teams in the fall, requires too much speculation at this point. The mechanisms are in place which allow Premier teams to move clubs, as has happened before.
CornerFlag,
Yes, it's a separate club that will only field challenge teams. As far as the way you state feeder teams, that's one way to look at it. Another way is for a common training syllabus for a much larger group of players, therefore, developing all area players. One answer on the why not merge is, the multiple business models between the area clubs lead to items which can't be overcome.