This was my planning for a realistic side a few seasons ago. You'll have to train positions for your players if you want that squad. Another flaw would be, for the players playing on multiple rows, DM/M/AM for example, how would you distribute their stats? Defensive, offensive or balanced?

GK
GK
DL/DC
DL/DC
DR/DC
DR/DC
DC/DMC
DML/DMC
DMC/DMR
DML/ML
DMR/MR
MC
MC
MC
ML/AML
MR/AMR
AML/AMC
AMR/AMC
AMC/?
ST
ST

2 GK
2 DL, DR, DML, DMR, ML, MR, AML, AMR, ST
3 DMC, MC, AMC
5 DC

The question mark stands for an extra position if I could get it, but not necessary. Below that is a summary of the number of players able to play each position.

Recently, in the shower and while sitting on the toilet, I managed to come up with a squad of about 18 players only, suited to playing my WM and rocket ship, though the squad would also be able to play other formations if necesary, e.g. the butterfly.