No. I think you misinterpreted. His theory was that if he existed, others existed as well. This was stated in Unbreakable and once again in this film. He was obsessed in finding ANYONE that resembled any gift. However, his first theory was to find his opposite, since he wouldn't know what other abilities they had.
Everything you're mentioning has no bearing on the plot which is to make the world aware of people with abilities. First to find them, then make them known. It was him (and the son) that convinced David to go out into the world and save people in Unbreakable. David has been spotted and photographed on his own. Okay, he learned about the Beast a few months prior, so why wouldn't his plan be to put David against the Beast? Once again, he's obsessed with comics and the hero villain fight. That's why the tower was irrelevant. He spent months/years looking for someone like David. Once Glass was in the facility, he knew it was a matter of time before someone else would be in there as well. He's been patient, and knows that they are being watched. Glass is an urban myth, the Beast was on the news, and Dunn had been making noise in the papers for damn near 2 decades.
One of the reasons you can say he was having doubts could have been because he was getting bored in waiting. The doc even implied that he had been out of his room before, and he's been tampering with things around the facility. Once he had enough pieces in place, game on. Casey is irrelevant to the plot. Glass didn't even want to kill Beast, just wanted Beast abilities on display. He had nothing to do with Dunn dying either, that was just collateral damage, he only guessed that he would die.