With that much line replaced, it's going to take some effort to bleed. Somebody has to sit and pump the brake, while somebody else works each bleeder nipple starting at the furthest from the MC (probably right rear) to the nearest.
Another option is to slightly crack all nipples on all calipers (rear cylinders probably on a 98 Jimmy) and just let them ...
If you mean that your crank journal is already 30 thou undersize and that is the limit, then no, it cannot be taken lower.
This means either a new crankshaft or, if the cost of the crankshaft warrants it, a build-up of metal on the journal surface with subsequent machining to size and heat treatment. A very skilled and expensive process - used on special ...
I think you are misunderstanding the reading on the stick. The Hot mark doesn't mean the fluid is overly hot... That is the full mark when the fluid is hot (which is normal). Transmissions are supposed to be checked after the engine is up to temperature and has been driving a while.
It appears you know what the grinding noise is, but you really don't ask the question of what's going on. I'd suggest one of the slides in the caliper bracket isn't moving freely or that one side of the brake pad in the rear isn't moving freely. You are going to have to take it back apart to discover exactly what is going on.
Reading hot on the transmission dipstick after driving is normal.
As to the ABS light they could of damaged wiring while doing the brakes but it's unlikely. Reading ABS codes requires a scantool capable of talking to the ABS computer.