Yankovich was the first Democrat to announce candidacy for the seat, but has only very recently moved to Wisconsin's First Congressional District from his home state of Ohio, so I think it's unlikely that he has much support here. Breit, who lives in Pleasant Prairie, is a member of Forward Kenosha, and Bryce is a longtime union activist from Caledonia, so the race for the nomination is probably between the two of them. (But see postscript below.)
Iron worker Bryce, who tweets under the hashtag "Iron Stache," has run for school board, State Assembly, and State Senate, but never successfully. He stood no chance in the 2014 State Senate race, given the Republicans' redrawing of district lines in 2011; he came in a distant second in the primary for the 2012 Assembly race (the unopposed Republican received more than three times the combined total of the two Democrats' votes), and also fell short in the ten-way 2013 school board primary.
He was ejected from the Senate chamber in Madison in 2015 for yelling that Wisconsin was "turning into a banana republic." He told the press that he had planned to testify against a so-called right-to-work bill, but when Senate leaders prematurely shut the meeting down, shouting was the only option he had left.
He wasn't the only person to get hauled out of the State Capitol since the Republican putsch of 2010, but that, and his very emotional inaugural campaign ad did help him raise $100,000 in the first day of his congressional candidacy. My own Facebook feed included some progressives and liberals who Ain't From Around Here talking about contributing to his campaign; we'll see how long that lasts.
Because Ryan can raise $100,000 over brunch.
P.S.: Janesville School Board Vice President Cathy Myers has now become the fourth Democrat in the race. Janesville is on the opposite end of CD-1 from where I live, so I don't know anything about her; but that is Ryan's hometown, and she has the endorsement of her State Senator.
