[B and C]

Take some white paper towels with you. Use them to mop up the wet. You can see if it’s’ green indicating coolant aka Aquahot leak, or just clear indicating water.

You are sort of describing the Aquahot heating unit. Hard to say without pics, and Newell put them in different locations depending upon the model year and the floor plan.

The box I described has 3(4) 3" flexible ducts coming out of it.  I think you may be right as there are a couple of 1" hoses coming from the Aquahot bay R5 across behind the box.  Odd that the floor beneath the box and the hoses are dry.  I will do more investigating when the weather breaks...17* now.  Coach is in heated storage for the next few weeks.