Do you still have interference?
 

R1 on 1st no outs, slow roller to F6, she tags 2nd for the force and goes to throw to 1st and R1 clearly interfers with intent to bust up double play. However, before F6 tags 2nd for the force B/R is already at 1st.

Do you have a 2nd out for interference to breakup a double play?

I assume you are not talking about malicious contact, which would mean that you are saying R1 clearly "illegally impedes, hinders or confuses the fielder". But if BR was at 1B already, how was F6 impeded, hindered or confused?

If there were any doubt in my mind as to whether there was a play being made on BR, e.g. turn the wrong way, did F6 make an errant throw because of R1's actions, etc., I would rule it interference, but otherwise, I'd probably just warn the player.

By the words you've chosen, you've answered your own question. If the umpire feels the interference prevented a possible DP, it's 2 outs. If BR is already at first ... where's your possible DP?

I also believe that there is no play therefore no int. Many argued with me.

Just thought I would see what you all would call/not call.

What did "Many" want called?

Hmmmm
 

If the batter/runner reached 1st base safely prior to the "interference" how did the "interference" prevent a potential double play?

Some sated that the act of interference is all you need without regard to the B/R.

The act of interference is all you need FOR WHAT?