PROBLEM SOLVED!

I unplugged almost everything, blew them out (to make sure there was no water, etc), and the problem ended up being the tail light plugs.

They were damn near drenched, but after blowing them out and letting 'em air dry, everything is working damn near perfectly.

Thank you everyone for your help, and hopefully if anyone else has the same problem, they can refer to this thread.

I'm beyond relieved it wasn't anything else, and I found it within a few hours (right before it got dark, haha)