On the surface, it’s easy to see how the “Meeseeks and Destroy” moment leads to what we see in “The Wedding Squanchers,” but some people need more convincing. In particular, Redditor u/demon_ix broke down why the theory doesn’t hold up, saying, “Tammy was already an undercover agent working to infiltrate Rick’s inner circle. The guy runs around the universe telling everyone his name is Rick Sanchez. Really do you have to be some kind of detective to find him once you track him back to Earth?”
If anything, the theory would only explain how Tammy became friends with Summer in the first place, to the point where she was invited to the Smith house party in Ricksy Business. She could then have used this party as an excuse to approach Bird Person and set in motion a series of events to take out Rick and most of his criminal cohorts.
After all, Tammy knew Rick had to be around; otherwise she wouldn’t have enrolled as a student at that particular school that his grandchildren happen to attend as well. And if Summer had never used Mr. Meeseeks to get popular, Tammy would have found another opportunity to befriend Summer or get close to Morty. But this is probably a development that doesn’t have much of a bigger scheme at play.