Foundation Issues - Cleveland, OH

[Niobe Burden Austere]

Dealing with a foundation issue brought to our attention during the home inspection on a SFR we have under contract in Cleveland. The home inspection reported a faulting retainer wall, basement moisture and foundation issues. We paid a foundation/drainage contractor, Adelio's Contracting Co, recommended by our real estate agent to review and give an estimate to complete the work. Are these estimates really accurate or a bit overblown because we are out of area investors?

To excavate and waterproof the basement foundation wall along the west wall, 6' of the north wall starting at the
northwest corner and 23' of the south wall starting at the southwest corner. Work includes:
- Obtain necessary permits
- Remove concrete where needed for excavation
- Excavate along the basement foundation wall and haul away soil
- Remove the existing drain tile line and downspout line
- Once the foundation wall has been exposed, cement parging will be used on any areas of foundation where the block is
exposed. Cracks in the foundation wall will be filled by using hydraulic cement and a rolled on elastomeric waterproofing
membrane will coat the entire foundation where exposed
- Sewer jet the drain tile and downspout lines from the trench
- Install new PVC drain tile with cleanouts, and downspout lines
- Schedule inspection with city building department
- Backfill with #57 washed gravel to 18" below grade
- Reinstall concrete where removed
- Reinstall existing topsoil

Estimate $20,755

As everyone is so booked out these days and we are under discovery phase deadlines, they could only give us a range for replacement of the retaining wall of an ADDITIONAL $20-30K for a subcontractor excavator to remove the existing retaining wall and replace it.

Plus to waterproof the remaining foundation behind the retaining wall is estimated at $6,150

Here are photos of the north and south side of the house and retaining wall -

If you have experience with these issues, your insight would be so appreciated.  

Thanks!