A1 goes in the lane for a shot releases the ball before coming in contact with B1 who has established a legal guarding positon. The ball goes in and A1 bowls over B1.
Offensive foul on A1 and the basket counts?

or not?

Was A1 airborne or not? If so, under what rules code were you playing?

If A1 has returned to the ground and the contact occurs before the ball goes through the basket, score the basket, count the foul.

If A1 is still airborne, and you're using NCAAM rules, score the basket, count the foul.

If A1 is still airborne, and you're using NCAAW of FED rules, it's a PC foul -- no basket.

"Team control" ends when the ball leaves the shooter's hand for a shot (Fiba rules).

The basket is no good. A1 is still an airborne shooter until he returns to the floor. If he passes and crashes it becomes team control then.