What is party?
Here's how you determine the party of a federal US magistrate judge:
He or she is selected by a vote of the judges of the district at the time. The chief judge has the most say in the selection.
So, let's see who was chief judge United States District Court for the Southern District of Florida on March 13, 2018.
The chief stooge of SD Florida was Kevin Michael Moore [chief from 2014–2021], appointed by G.H.W. Bush [Grabby Poppy, the Deep State's Stooge of Stooges].
Most of the SD Florida stooge-judges that would have voted for him were Clinton-Obama stooges, with a mixture of Smirking Chimp stooges.