Questions to ask plumber

Hello,

It looks like we have to replace one of the drain lines running under our house - going from the kitchen probably to the laundry area. It will involve jack hammering a hole in our slab floor in two locations.

I'm trying to think of good questions to ask potential plumbers.  I think there are issues I have to consider such as

* inspection of the radiant heat system after the work is done

* uneven settling or cracking as the replacement cement cures.

* will we have to re-open a hole if other lines corrode.

I was wondering if you have done this and what other questions or issues you might have run into.

Thanks!