If a state prosecution is moved to federal court then President Trump would just pardon him.
Based on what I read, he could not. Under Article II, Section 2 of the Constitution, the president’s pardon power is strictly limited to offenses against the United States, which are federal crimes. Moving this case to federal court would not change it to a federal crime. It would still be a state crime.
On another related note: Minnesota sued the DOJ and DHS for withholding evidence needed for a charging decision.