Rosentstein played both sides. It was going to come out, so he released it.
He did whatever was likely to advance him with the side that appeared to be winning at the time he did it. So, I totally believe he would have worn the wire, and connived with Comey, but at the same time, as the Witch Hunt started to unravel, would cover his bets by throwing Strozk, Page, and McCabe under the bus.
I was immediately wondering “why would he do that?”
Your postulation makes sense except he released those text messages very early, way before it started to unravel. Besides, he knew that it would come out that it was he who released them, so wouldn’t that argue against him doing that?
Saving his own ass from prison is a good motive.
Trust nothing of what this little weasel says, not one word.