could easily be the ABS module as well or wiring. search here in this forum for TRIFECTA by bluebee, rest her soul, there are lotsa posts in the thread, but it will get you thru checking every wire that needs to be checked and how to do it.
curious...does the ABS and DSC light come on when turning the key to pos 2, then the ABS light goes out with DSC still lit, or does the DSC Light go out then return when driving?
when you say the ABS works in your post #8, have you tried to lock the brakes on wet pavement or are you going by what the lights are telling you?
btw, regardless of what you were told by the rebuilder about the creator 310, its a questionable unit, got one long time ago and got thrown down many a hole cuz of it, i ran a screw thru the middle of it and it now hangs on my garage wall.