What tools will I need to clean up a sump pump mess?

This sounds like a HazMat scene.
You may need to get a professional mold removal job done. The mask is a good idea BUT need to have the mask fitted and thoroughly cleaned after every use. You would also need a full body suit if the walls are totally covered with mold and mildew. The studs, walls and flooring that were wet have to be replaced.

I would simply call Service Master.

It is what they do.

You can’t treat what you describe as a DIY job. You can’t save enough money to make it worth your while and get a good outcome

Thanks a lot guys!

Do you need to do mold remediation? If so, expect to pull out just about everything down to (if you are lucky) the wall studs, and treat that with mold remediation of some kind.

This happened to the foreclosure that we just bought (before we bought it). The bank did the remediation, but now we have to add all the walls, electrical, plumbing, furnace, everything.

Clorox kills mold but it depends on how bad it is whether you want to do it yourself. In a basement I am assuming you don’t have plaster walls, or do you? I guess newer houses do. I only ever had one house with a sump in the basement and it was old and had stone walls. Probably above suggestions are better than my do it yourself.