rent a carpet cleaner , use vinegar + dishsoap (not too much because of suds),went 2 times over every inch of carpet, then 4 times just with the vacuum setting and extract EVERY BIT OF WATER (!!!

., you often get more flies with honey than vinegar). 

I read somewhere you weren't supposed to use bleach on black mold that vinegar worked better.

(salt water melts iced goo quicker).i would replace/reset the wax ring (they also make waxless now: rubber cone or foam type). i like to use 2: one is the oversize one, and a regular one to "butter" around any gaps to the connecting tile floor.i would use some lye (about twice per year) (please no drano) or baking soda and vinegar left to bubble followed by large amounts of water.extreme DYI: use a dry/wet vacuum on the push (NOT pull) setting

Maybe it wound up "growing" something in the sump, any way.My question is:Do you think it would damage anything if I dumped a couple gallons of distilled white vinegar down there to see if it would loosen / dissolve the scum?

That is what I do and what I suggest anyway, you win more with honey then vinegar. 

Probably because I, like they would be, was still recoiling from the sting of your bile and venom.You'll get MUCH better results with honey than you will with vinegar!

We do all the work ourselves, and I've had good luck using straight or diluted cleaning vinegar to get rid of smells without the fear of bleaching anything you don't want bleached. 

Then I put a half cup of baking soda and a half cup of white vinegar in and let it foam and wait 10 minutes.

White vinegar, Dawn , water - mix and mop .