Good googamooka, either he is in or he is out. What is so hard about that? Your UC and DC and DoFS (Boy Scouts?) and CSE have NOTHING to do with this. All they can do is nod their heads and say "okay" to your Pack Committee/COR's decision.
This problem is for YOU, your Pack Parents, your COR and IH to solve. If he does not sign the proper papers, take the proper training, get the proper clearances, he is NOT a Scout Leader. If he refuses to "play nice" and cooperate with the other parents (your committee !) and work for the good of the Pack, he needs to be sat down with a BIG cup of coffee, and dealt with. End of story. Give him the letter. Speak with your lawyer.
As for the mother, are you sure she would be a good choice? The wannabe CM will always be in the background. The resentment will always be there. She will have a difficult time too, dealing with his "controlling" behavior. I would hope you could find a proper , not tempo, CM who would be willing to "sign the papers, take the training, get the clearances, play nice " and KiS, MiF for the Cubs.....
. . . that they used in their light sabers.
I've been wondering why the movie was called "Drum Taps," since there are no drums. Maybe in an earlier script the signalling was to be done with drums, and at some point they decided to switch to the heliograph, but that would not have made a compelling title.
Interestingly, the characters were able to see what appeared to be brief random flashes and interpret them in great detail, including the names of the individuals riding into the pass.
It was also kind of funny that while the hero, Ken, clearly admires the Boy Scouts, his own knot-tying skills are not particularly good. He surprises and ties up the two outlaw guards of Rocky Pass, and they almost immediately slip out of the rope and ambush Ken.
I'll say it one more time and then I'm done: you have the power, responsibility, and the authority to ask this man and his girlfriend to leave and stay away. It's your decision and you don't owe them an explanation. If he goes to council, then you can have that special meeting and present your evidence. If he goes over your head to the COR or IH, again, you can have that special meeting and present your evidence. You approve leaders in your unit. YOU!
If he doesn't get it, call the police. It's really that simple.
One of my favorite campouts as a kid was to Camp Rock Enon in Gore, Virginia. What I liked best about that trip was that we didn't sleep in tents --- they had these log-cabin lean-to shelters called Adirondacks and a whole patrol could sleep together in one. Wonder if they still have those Adirondacks....