@Bruce Woodruff,Thanks yes I am considering using soundproofing underlayment underneath the new vinal floor, so please let me know if you know of a specific product.Regarding the code requirement you are right here in CA The minimum ceiling height for the living space and bedroom is 7 ft, the bath could be less than 7ft but not too short.

Why is it a problem, the actual shift is not noticeable when happening (most likely).Is it non closing doors, floor in the kitchen (for instance) sagging badly near the stove.Maybe get guy under there to shim up the low spots closer to level in some areas.Since you lived there it might have gone way out of wack in some places.They need to understand Texas has muck for soil in some places.Good Luck!

My impression from the Andersen installation guide is that a flap of WRB should be lifted up and flashing tape installed underneath this.

., installing a new toilet, what if soil stack needs replacing?).

Something on top because many hotels do have a firm foam mattress underneath.

*if it happend and replaced the tub make sure the drainage and overflow connection are good and test them before closing walls, also make sure they use enough thinset as a bed underneath the tub and a waterproofing plastic sheet under that thinset ifit happend to be on plywood (if raised foundation).

I put a small string underneath the flapper to let it run a tiny bit... that kept it from freezing but it ran the water bill up quite a bit.

She shouldn't have parked underneath the tree if it was dropping walnuts. 

The lot is .4 acres, with good loam soil. 

I do realize that leaves you with a task of finding a house flipper that is willing to allow you to learn underneath him and that might mean you work for him wile you are learning or possibly paying him or whatever but there is already enough resources out there on finding mentors.