A1 rebounds missed free throw. While still in 3 second lane gets fouled by B1. Where is the spot for ensuing throw-in?

Thanks

Endline on the side of the basket where the foul occurred.

what about
 

What if B1 (defender) gets rebound and while still in paint gets fouled by member of shooting team?

Thanks

Why would it matter? The spot of the foul is what's important to determine the spot of the throwin, not whether the playe is in his front court or backcourt. It's the oob spot nearest the foul, and always on the side of the lane rather than underneath the basket (outside the paint).