Subs After Made Free Throw

[Wondering]

This has to do with bringing in subs after the last made freethrow.

The "Substitutes" discussion in a recent post by "Just Curious" seemed to conclude that subs after the last made FT were OK, even if they were not for the shooter.

This seems consistent with rulebook 3-3-1c "During multiple free throw personal fouls, substitutions may be made only before the final attempt in the sequence and after the final attempt has been converted." In addition, para (d) says they may enter anytime the ball is dead and the clock stopped - which is the case as the last FT drops out of the basket.

There doesn't seem to be any restriction in 3-3-1c on how many subs or for who they are coming in for.

My question is this. Which is official is responsible for bringing them and what is the procedure if the non-shooting team immediately grabs the ball?

I assume the Trail is the responsible official since he is facing the table. But he is also fairly busy counting and watching the players until the ball drops thru the hoop. At that INSTANT is the Trail required to check the table and immediately - before the non-shooting team can grab the ball - and whistle if there are subs reported at the table?

What if the non-shooting team grabs the ball as it falls out of the net? Should the Lead take the ball away so subs can come in?