Vanlife Q&A: How should I go about patching these holes on the floor?

In this post in the Van Life Q&A, a user asks:

How should I go about patching these holes on the floor?

My thoughts:

That looks like a hole for an RV toilet flange. Get some metal sheet, screw it down (or from the bottoms and use a sealant around the hole and edges of the sheet as well. Other holes were probably for water lines and electrical cables.