I may be wrong (and I often am :-), but I doubt Cao will win re-election. Even as a moderate (or RINO, if you prefer), he’s still a Republican in a seat that’s been Democratic for generations. I have to think any Democrat not as damaged as Jefferson was could win the seat back without too much difficulty.
Unfortunately, I think it will be the same with Brown. You know when he’s up for re-election the Rats won’t pussyfoot around, they will bring in a big gun on their end.