MLB call vs softball

[Tru_in_Blu]

I was watching the Red Sox @ Blue Jays yesterday.

There was 1 out and runners on second and first.

Batter hit what appeared to be an IF.

The runner from first initially took a couple of steps towards second base and started back to first base.

The first baseman was coming in to make the catch and bumped into the runner. Despite the collision, he was still able to make the catch.

At the top of the screen, I could see U1 extending his right arm horizontally. I hoped to see that again, but the replay didn't have him in the picture.

The ruling was that the runner from first base was out due to interference and they placed the batter on first base.

So I'm wondering if the scenario plays out differently if it's a softball game.

First of all, I'm not sure about the signal that the first base umpire was giving. But, I've worked with plenty of umpires who call a delayed dead ball with their right arm.

Secondly, why (if that's what he was calling) would it not have been an interference call with a dead ball right away? I've heard baseball doesn't have a "dead ball" call, so maybe that was part of it.

Lastly, if this had been an ASA softball game, would we have an immediate dead ball, R2 out due to interference, and possibly batter out as well due to IF?

But 8.7.J.1 (does this negate the IF? Remember those many discussions as to when the batter is out on an IF? I maintain that it is when the status of the ball becomes known.)
Effect:
A. The ball is dead.
B. The runner is out.
C. The BR is awarded first base.

Only Effect "F" would result in 2 outs on this play if the ball was not caught.
F. If the interference prevents the fielder from catching a routine fly ball, fair or foul, with ordinary effort, the batter is also out.
If F3 was a rules guru and after the interference simply let the ball fall, could that warrant the 2 outs call?

Same or different for baseball?