Rolf, as for making the repairs just remove and replace the flooring-it will probably deteriorate quickly anyhow. If you have wet studs and plate- cut wallboard 2’ off the floor and dry them then bleach and kilz paint, wainscote the wall and you are out of there. This job doesn’t sound any worse than typical floor repair to me.
It does sound as if you are concerned about liability issues, I would suggest making the repairs before bringing it to your MHP, and if your repairmen are loose-lipped, don’t use them on this job.