I don’t know if this has been said as i haven’t been following this thread too closely but i had good luck with stuck bleeders by tapping the tip of bleeder with a hammer, then try to tighten it first then loosen, then repeat if necessary….
The brake line SHOULD just unscrew from the back of the cylinder however there are times where the line will also want to twist with it, if this is the case then unmount the cylinder from the backing plate and unscrew IT from the line instead of trying to unscrew the line. I often crip the rubber brake line when doing this type of work to help keep too much fluid from bleeding out as it makes for shorter bleeding when your done. I would normally only bleed the wheels you are working on but you could also bleed out the fronts to make sure you have new brake fluid all around which is not a bad thing. Lastly make sure you really need the cylinders as you don’t need to replace them if they aren’t leaking.
Yeah, this is what I ran into on my Cutlass – the hard lines were secured both at a flexible line mount and at the cylinder. I unbolted the bracket holding the flexible line mount, and then put an adjustable wrench on the flex portion while I used a flare wrench on the hard line side. then I pulled the cylinder and hard line out together. Install was the reverse. Just a note here, flare-fit lines are notoriously difficult to hand thread. I had to unbolt that bracket just to make sure I could re-mate the hard line to that fitting. I found out trying to thread the hard line to the wheel cylinder with the cylinder in the car was completely impossible. 3 of my 4 wheel cylinders were bad when I did this, so I replaced all 4.