Safety concerns and precautions in setting up a workshop/studio in the utility room
I don't see any cause for concern with your intended use of the area. However, things don't always work out like we plan.

Therefore, a double-the-capacity Bath Exhaust Fan, Exterior Wall Fan or even a kitchen Range-hood (to be down much closer to your work...can be mounted to slide up and down) would be ideal.

Such an exhaust can be switched on and off only as needed and can act quickly to the demand. The installation of an Exhaust Fan intends to flow clean air past the furnaces and water heater as your fumes and dust exit the house while never coming near those appliances.

Yes, an Exhaust Fan can create a negative pressure scenario that could possibly draw CO from those appliances, but most homes leak enough air for that not to happen. Just keep your workspace Exhaust Fan, if you choose to install one, within a finite ability.