The only FPE breakers in question are the Stab-Loks.
The breakers lost their UL listing in the late '70s or early '80s, but gained the listing back in 6 months or so. The Stab-Loks were only available in 15-100 amp ratings.

There were no problems reported with any of the other FPE breakers; in fact the FPE breakers were factory installed in some non FPE brand panels.

I think their transformer division is still alive and well (I might be wrong about this, though)