There isn't a chance on earth rumours about Sterling moving to Arsenal are true. Move from a team you are first team, fill the home grown quota well and have been performing excellently under Pep, to go to Arsenal for no champs league, less money(long term), less sponsorship coverage not being in the CL which again leads to less money from sponsorship deals for himself and far far less success... lol
No chance he'd move in a million years, if Sanchez does join the players most at risk are either Silva or one of the central midfielders. Silva is 31, he's not getting very many assists, scoring has always been low. He got 7 assists to KDB's 18 last year. So if anything I see Silva being moved on by next summer, Sanchez/Sterling out wide and KDB in the no.10 role, but with all three players able to rotate. One of the issues City had for so long was so little pace on the wings, with Silva often playing wider but so unable to play it effectively.
Another option is going way more offensive and having less defensive type players in central mid and pushing Silva into central mid, KDB ahead and Sterling/Sanchez wide. That is though, Silva/KDB, none of them are anywhere near Xavi level defensively so would make for a very weak central mid defensively.
Sterling/KDB are guys to build that team around over the next 5+ years, Silva isn't, even Sanchez I wouldn't necessarily see sticking around very long as he's already 28.