Call the firms and see if there's any chance of an expedited decision. Maybe also call the judge and see if there's any room or if it is possible to spend half your summer with the judge (this is a bit riskier of a call - calling the firms is a must).But by no means should you let the job with the judge lapse without an offer from these other firms.
I would check with career services before you ask for more time or to spilt. When I started the interview process with federal judges, I was told that it was very rude to turn them down. It looks bad on you and the school. I was told that your not supposed to apply to work with a judge unless you would happily accept it on the spot. Congrats though.