My understanding of the situation was that USFS originally had Aljona move to the US for a cushy coaching gig - essentially helping USFS develop their pair's teams and pair's program out of USFS's home rink at the World Arena. After Dalilah left, they needed someone to fill that pair's coaching and leadership hole and Aljona is certainly a big name in the pair's world. For Aljona, this would probably give her a good salary, some job security, and lots of connections that could get her students - which she might have needed if the rumors about her being difficult to work with are true.
Then, somehow, she got in touch with TJ and Dalilah and was offered an opportunity to compete again and took it. Of course USFS would jump at the chance to have her compete for them considering her past success, but it still seems at this time they primarily wanted to make her happy so she would coach for them.