can the broken exhaust bolts be extracted without taking the manifolds off?

Usually you take the manifold off and use a guide (www.rodneydickman.com) to drill out the broken bolt, or if there is something sticking out from the head, then weld on a nut.

In my case, I had to pull the head so I could drill out the bolts and also had a machine shop weld in a stud (instead of using a helicoil).

Feel for the bolts on the front exhaust manifold with the engine cold. There should be one above and one below each exhaust port. If you have more than one broke/missing plan on taking the head off.

if go to take off the manifolds completely,are all the bolts going to break.

Theres a high chance they will if you didn't shower them with PB blaster on a daily basis for a good few days.