Pardon the dumb question but since we only have the internet, how much fluid did you use to bleed?
They can take a lot of fluid, like 64 ounces, to get all the air out when the system is significantly exposed to air.
That still doesn’t explain the original loss of pedal which sounds like rear rust. The rust can be layered and sort of soak and deep rather than spray and drip. And it can be on top of the gas tank, all this can make initial leaks hard to find.