IMO a hand impact tool is your best bet for the other two; but it may snap them off too. Start out with fairly gentle taps on the tool, and work your way up gradually. You may have to create a custom bit for it. Here's a shot of one I made to get an antique tractor carburetor apart (and it worked great)
For the broken one, I would probably try to center punch it as close as possible to the center. I'm not certain, but there might be enough hole exposed to use a "transfer punch" to hit center.
https://kk.org/cooltools/transfer-punche/
Then drill it out in small steps, stopping either when you can see threads in the hole or there is just a thin shell of the bolt left in the threads. Then break the remainder apart with a dental pick. With luck, you can save the hole.
If not, it is possible to make, in effect, a thread repair insert. I used a SS bolt in 1/4-28, drilled and tapped to suit (in my case, it was 2BA for a Tenax stud, but I think yours might be 10-32 instead), and held in a split nut so I could cut it off to length. Kind of tricky working with such a small piece, but it came out great.