This is no different than this situation. My ruling is for OBR since I don't know the Fed rule which may correspond. Rule 7.09(e). If there is a play possible on R1 then R1 is out. If there is no play, then there can be no INT.

Play: R1 is stealing. Batter strikes out. On follow through, steps across the plate and INT with catcher's throw. Since batter is already out, he can't be called out for INT. So, R1 is called out for teammate's INT after being put out.

So, it depends if defense has a play or not. If they did, rule INT and R1 out. If not, read batter's intent. If intentional, stop play and put R1 at last legally acquired base before INT. If not intentional, let play go.

This is how I would handle the situation.

I assume "on the transfer" means F3 dropped on the transfer. If the BR who was out unintentionally makes contact with the dropped ball I think I would have live ball, play on. If intentional then dead ball, runners return TOI.