I do not know about the DH, but players on the field can switch positions any time during dead ball time, and switch back next hitter.
If one leaves he field, he is done for the day.
Joey Gallo went 3 for 4 in game this year too.
IF, if Chicago is a bad as so many here say, this series mean nothing for Twins batting numbers; wait till the next two teams that will be a better sample.