Interference, or no? How many outs?

[BoomerSooner]

I don't think there is a call to be made here (except for the out on the on R1), unless by chance the slide was malicious or illegal in some way. Without seeing the slide, my first inclination is to assume it is a routine slide where the play is close enough for the runner to justify sliding.

That said, after reading the OP again, I could see an interpretation of the play that has the runner initiating the slide late (as in too close to the bag such that it is interpreted as malicious) or unnecessarily sliding (as in the runner had time to stop and peel away or kneel to get avoid interfering). In those cases, you could call interference. My gut is still telling me this wasn't one of those instances and thus not interference.