here is the link to the original guide by ZR0rschach: https://steamcommunity.com/sharedfile...

I also left the required text file command here: +PlayableCharactersV2=(BaseId=0, Id=11, Name="Batman_OneMillion", bBad=false, Mask=0, LockedSkinID=ESkin_1Million, bIgnoreLock=true)
+PlayableCharactersV2=(BaseId=0, Id=9, Name="Batman_N52Metallic", bBad=false, Mask=0, LockedSkinID=ESkin_New52Metallic, bIgnoreLock=true)

thanks, ZR0rscach!