I just want to say thanks for all the help and guidance. Im amazed at how much knowledge it takes to own an RV. My head is still kind of spinning.
From what I gather I've solved #1 and #3 in that I splurged today and got a hydrometer. After letting the batteries sit from a charge my voltage meter read 12.62 but in testing the gravity of the batteries. 3 cells registered zero charge.
So I've concluded that the capacity had been greatly reduced and that's why we don't get to enjoy the simple pleasures we bought the coach for.
#3 seems to be related to a faulty or cheep plug and is soon to be replaced by a heavier duty one.
#2 - the WFCO controller rather than the PD 9200 is still a question and why it never enters "boost mode" is yet to be answered except perhaps because the batteries were faulty. I don't know. I'll look into that after I change the batteries.
I'm going to look into Katanapilots idea of upping the battery size to group 31. Solar is for sure in our future as well.
I'm still looking into the fridge heater. That whole post felt like Alice and Wonderland and the rabbit hole to me.