Yes I would agree to put him in a big cage to train again.
I'm so sorry your going through this.I'm sure this will pass.Poopy problems usually do go away.
CCL..I think your Rosco has UTI.You should try to bring a pee sample in or just put him on Clavamox 2 times a day for 2 weeks.I did that with Tucker and his peeing outside the litterbox stopped completetly.That's just what I think but It may be behaver problems..but with peeing It usually is a start of infection and would get worse.I may be wrong.
Good Luck to you guys.
Meg this should get better with retraining..I'm sure..I hope.