Acosta is on final year of contract, and they seem more interested in getting him sign new long term deal (apparently he's been making noise on social media about a raise), so he most likely will stay - depends on how quick they can re-sign him to new deal - how much time he waits and thus becomes cheaper for another club to bid (free next winter). Right now only middle-east interest, but I think he has the talent to play in EPL/Serie A at some mid table team he would be useful.
DC played 4-1-4-1 at start of last season, all AMFs ahead of young DMF Durkin, they changed to 4-2-3-1 when Rooney came (SS), and Arriola was more often at RB instead of RMF/right AMF then, and Acosta took sole centre AMF role (wanders to wings though), Asad was on left and Segura got more time on right, Zoltan Steiber seen more bench - to me Steiber is the one that will have to be moved, he makes 2nd most money behind Rooney but is not an integral part of the team just a nice piece to bring on - it makes sense to move him free up his wage and give it to Acosta basically in a new deal.
It also depends if they get Asad back on loan or sign him, DC have a lot of AMF type players in the team (at least 6!? Arriola though is experimented at RB) and the 4-2-3-1 was the formation that shot them up the table, I can only assume they will only have 3 attacking midfield spots available, but if they can't get Asad back and move Steiber, that is only 4 and Arriola is maybe at RB, so only 3 players remain as options. So right now both Rogriguez and Acosta would play, only thing is if this 21 year old can immediately transition and be dependable for whole season.