Ione/Sloan Questions

How exactly did their switch occur? I know Sloan was going on about how their minds would swap. I'm assuming she's saying this was possible because as evidenced by Riley's shoe near the beginning (near the pic of Sloan and Verge), and the poster above Riley's bed, the movie is merely the next cycle in a time-loop. So she would have already gone through all this and grown up knowing it would happen again (I think... actually a bit hard for me to grasp all that)? And how did all this occur by Sloan getting abducted by aliens in 2011? It shows the abduction, followed immediately by their 'flip-flop'. Was Sloan returned in-between, and granted the ability to swap minds by the aliens? And even if all they're doing is swapping minds (and this is the biggest mystery for me), then how did Ione in Sloan's 1992 body come to possess her phone from 2011? Also, did Ione avoid all mirrors in 1992? Why wasn't she freaked out and confused as to why her mother's body looked identical to hers? I like the consistency of this movie for the most part, but this stuff with Ione and Sloan didn't seem to be as well thought out.