Well, since you're 96-51 with that team, I would say you are doing just fine.
James (A) has a .962 fld % right now, with 1 plus play and only 4 minus plays. He's suitable, combined with the fact that he has an OPS over 1.000 I would say just leave him there. He's Babe Ruth, with a Derek Jeter glove, at SS.
Moreno (C) did decently at AAA playing SS. .945 but 41 plus plays and zero minus plays.
Wilfredo (B) is just OK.
Sakamoto (91-91-94-92) is a guy who will win the GG almost every year, if you want to play him despite his bat...which is terrible.
So James plays SS, Moreno plays CF, and Wilfredo plays 3B, just like you are doing right now.