So, what you are saying is that something like this was possible:
1. LBJ’s team decides that Oswald needs to be made to permanently stop talking.
2. Someone on the “LBJ team” gets to Jack Ruby and makes a promise to pardon him to get rid of Oswald. I’m guessing they had some blackmail on Ruby that was included in all this.
3. Jack Ruby does his part of the deal.
4. The “LBJ team” gets amnesia and becomes unavailable to Jack Ruby to make good on the deal for a pardon and other forgiveness on shady Texas activities by Jack Ruby.
5. The “LBJ team” arranges for Jack Ruby to stop talking permanently.
P.S. I could see a scenario where nobody that LBJ knows well was involved on these activities. What they would have just need to believe was that LBJ would take a more favorable path on some decision(s) than JFK. For example, look at Sirhan Sirhan and his views about who should not be the 1968 Dem nomination. I don’t blame Hubert Humphrey for that. I blame Sirhan Sirhan for that.
P.P.S. Occam’s Razor is that Oswald acted alone. Nevertheless, I wasn’t yet born until years later. So, I can’t know for sure.