My guess is that there already is a warrant out there.
Most warrants are served passively. If you get stopped for running a stop sign or a vehicle code violation, the officer will likely find the warrant and haul you off to jail.
However, the state that issued the warrant has to send someone to come get you. If CA does not inform MI that it intends to get you, MI would not be able to hold you in jail very long on the warrant. Still, it could be a very inconvenient two or three days. Of course, it is alway possible the CA will send someone to get you. There's no way to determine this one in advance of it happening.
The convictions and failure to complete your probation probably will turn up on a background check. It probably will be a "deal breaker" in terms of getting a decent job. However, most entities running these background checks probably are not going to report you to the authorities as info is sometimes erroneous or out of date. They will cover themselves with a prospective employer by suggesting it do some further investigation to verify the accuracy of the negative info. What actually will happen is that you won't get the job.
If you want to spend the rest of your life wondering when this thing is going to bite you in the rear end, then you do as you are doing now. If you want a future of very low level jobs, continue to do what you are doing now. Murphy's law dictates that the warrant will get served on you at the worst possible moment for you, such as when you are on your way to church to get married, etc.
Will the people you are iving with get in trouble? Technically, they are harboring a fugitive from justice, which is a crime in most, if not all states. It would be up to the local DA to file the charges. There's no way to know whether he or she would do so.
I recommend that you contact a criminal defense attorney in CA and see if there is a way that you can take care of this matter. It probably would help if you can now pay in full the restitution.