dare I say it..
Before I gave up, I would be tempted to use job weld on the oven cracks and holes. Not the liquid goop type, the putty type.
The putty type comes in a tube about the size of a roll of quarters, you knead it a bit, until the 2 colors are mixed, then mold it to repair any area. The consistency is similar to play dough.
It is pretty tough stuff, and easily smoothed with a wet finger during application. I know of a tractor engine block repaired with it, and I personally did an invisible repair to the bathroom sink of an ex mother in law after her idiot son dropped a hammer from ceiling height, knocking a hole in the sink. I applied thickly, smoothed with wet fingers, lightly sanded after curing time, and covered with several coats of enamel touch up paint. This was 5 or 6 years ago. She is still using the sink, and the repair is still undetectable.
for the oven, one wouldn't have to paint it, once cured it is a very dark gray. After it cures, I would turn on the oven for a half hour to an hour to bake out any residual smells, leaving the kitchen windows open during it of course.
It's worth a shot, at this point what have you got to lose?