rear brake cylinder vs sheared bleeder valve dilemma

[lintcollector]

Trying to bleed the brakes last fall/winter we ran into a might bit of an issue. The bleeder valve was rusted solid, so it came off in the ratchet. Waited until it was warmer, and promptly had the same result on the other driver side.

While it's nice to have things match, I've tried to drill out & use both an Irwin and another other mickey mouse brand broken screw remover, no offense intended to Walt Disney & Friends. I used the "rust remover" WD-40 and PBBlaster to try and get the sheared off bleeder screw out of the back. Nothing has worked, other than my daughter learning a new word or two. She resembled this:

I can get the rear brake cylinders off both sides and replace them ($12 AutoZone or $70 LMCTruck) or find someone with a torch & try to warm the rusted bleeder screw free.

Will heat ruin the innards of the cylinder? Is there another way to break that nifty sheared part free?

The below pics are:

1) Before neat words were uttered
2) After trying to fix/free the sheared off rear cylinder
3) Pretty original I'd like to keep because old is cool