100% correct, not even the greatest loser, conman CAN KEEP HIS OWNS LIES STRAIGHT !
I think that's why he's better understood as a cult leader or mesmerist than a traditional con man. Normally con men have to be fairly sharp, to keep their various lies straight in order to maintain an internally consistent reality for their marks. You can't be telling people you're a Nigerian prince in one communication and a Spanish prisoner in the next, if you want them to fall for it and give you money.
Religious leaders, though, are a different matter. Since faith, by nature, is belief in the absence of evidence, or even in defiance of evidence, you don't need consistency. The doublethink of believing two contrary things at the same time is something people are proud to do as a leap of faith. Jesus is fully human and fully God at the same time. There's no need to tell a consistent story, when people are in a religious mindset... in fact, consistency interferes with that mindset, which thrives when people are disoriented by self-contradictions. Those can be vaguely understood and embraced as "mysteries of the faith."
Trump operates more in that mode. One of his key techniques is similar to when a hypnotist (or ad man) repeats the same simple thing over and over until the weak-minded have internalized it ("you are getting sleepy," "there is no god but Allah," "A Diamond is Forever," "Crooked Hillary.") It's not a pitch to the conscious mind. It's an attempt to bypass it entirely through repetition in order to build an automatic subconscious response.
He doesn't have to make a cogent argument for why it's a "lock her up" offense for Clinton to have unwittingly had a few bits of classified info among her tens of thousands of emails. He just has to say "lock her up" over and over. And he doesn't need to make a cogent argument about why it's OK for him to have been found deliberately hiding some of the most sensitive top secret information at one of his businesses. He doesn't even need to settle on a single excuse for that, the way a good con man would. He can spew out a bunch of mutually contradictory talking points, linked only by emotion, and count on his cultists to take a leap of faith to back him.