"Why would Dan and Sierra not trust (Mike) at this point? Has Rodney convinced everyone that the one to get out after Joe as the most threatening is Mike??"

I think it's the exact opposite. Rodney would NEVER have mentioned targeting Mike to Dan and Sierra. To them, he must have been saying Jenn and Shirin had to go next since he wanted to wait for F7 to pounce on Mike. At F7, he wouldn't need Dan and Sierra anymore.

Mike told Dan and Sierra that he overheard Rodney saying that they were voting against him next and that they formed the Final Four. We clearly heard Dan's reply to that: "I can tell you that I saw us all as tight. All of us have talked about final 5, 4 and 3. All of us have. We are all looking at the end game. It doesn’t mean they are going to make the move early.”

In other words, Dan didn't find it odd that Rodney spoke about Final 4 to Tyler, Carolyn and Will because he saw it as a way to keep them in control until Jenn and Shirin left. It was something that they all did.

Dan still thought the 4 Blue Collars were tight, that Mike heard Rodney lying to the other voters. In Dan's mind, Tyler, Carolyn and Will were the ones being used until the Blue Collars gained majority. Then Mike's dickhead move at the auction made them think he had gone mad. It excused Rodney's attacks on him but Rodney probably still didn't tell them that Mike was his real target and that he was bummed to see him immune.

While Jenn gave her side of the story, I wouldn't be surprised if Mike voted against her to prove his trust to Dan. I'll leave the rest of my thoughts on that for the editing thread.