Injury replacement
 

So this happened last week:

Time-out is called for an injured B11. While B11 is being attended to by trainers, another team attendant (we found out later it was a water-girl, not a trainer) comes out onto the field and helps B24 stretch his calf muscle.

B11 obviously needs to be removed for 1 down, does B24 need to be removed also?

Since there is no indication, "An apparently injured player (B24) is discovered by a game official", causing the clock to stop (already stopped got B11) and doesn't cause the subsequent RFP to be delayed (NFHS 3-10-a), the action towards B24 seems appropriate preventive maintenance.

The player for whom you called the officials' time out is the one that has to be removed for a play by rule. What the others do during that time (as long as it doesn't violate some other rule, like going over to the other bench and taunting them or something) is of no concern to me. If he's over listening to his coach or getting a drink or getting a massage or whatever, so what? As long as he's ready to go with the rest of them, this is a non-issue to me.

Yup