Easy.
Rafe = Hooked up with Beck. (Maybe she's jealous, or just wants AOut of the picture so it can go back to just being her, Beck, and Hannah?)
Eric & Rickie = Roommates, friends of no neck Beck.
Amber = Girlfriend/leech to Beck.
Becky seems quite manipulative herself from what we've seen, and it's a solid guess that Eric and Rickie didn't want Amber to move in but caved eventually, either due to Beck or AOr both. Becky also seemingly has her shit together, at least compared to the rest of them.
I don't think this was Becky's shitstorm though, she just played a part in it. It was all about Amber's cats and Amber being an irresponsible pet owner and shitty friend after all. I say give it a few months, the whole "Becky/ E&R" thing will eventually blow up in Amber's face. It always does with her.