The problem with Trump's 'set up' as you suggest is that Mueller has built a solid/respected reputation over the past few decades.

Trump's (and the alt Right's) usual cries of 'fake' or partisan, just won't work against him.

Also, if Mueller does ultimately produce a damning report that is supported by hard facts, it will be very difficult for the Republicans who do support the rule of law to remain silent. (especially if Trump's popularity remains in the 30% range and he's seen as neg. in the midterm elections)