keep a close eye on them. u probably brought them in with u. i fought them a few different ways. u may want to get these no pest strips. they are at home depot. just keep an eye on it. be careful what u bring in from the outside.

I would not remove plants u are already fighting the battle just stay on top of it.
I dont think its infested but those things can put up a battle.

jUst do a bunch of searches on spidermites and battle them different ways. As long as u keep on top of it u should be ok.

I used no pest strips, insecticidle soap and foggers. This time of year is good because its going to be getting colder soon and that should knock them down. I found mine at the beginning of summer fought them for about 10 days and they never came back.