Stop trying to convince people to do what you want them to do and instead laser in on exactly what you could do to help, no matter the situation.

The inspection suggested waterproofing in the carriage house, and 1-2 pilasters/I-beams in the duplex. 

-Flooring/Paint $3-5/sqft-Kitchen $6-10k-Bathrooms $2-3k per-HVAC $6-8k-Roof $7-10k-Electrical $6-8k-Plumbing $6-8k-Foundation depends on whether it's slab or pier and beam, but I would consult a licensed expert on a case-by-case basis.

One set of drains from a shower had at least 5 vent 90's in it behind a wall & below the floor to get around beams & studs.

Its a relatively easy fix with the right contractor, Ive gotten quotes around $8k to install vertical I-beams around my basement perimeter. 

Well of course that's a change order... replacing a beam that you didn't know about?

Now I have to add beams and structural walls then sister the joists and redo the roof.

I had water standing under the house and it was on pier and beam and you could tell the water was going to cause a settling issue as well as moisture issues. moisture leads to mold and that is not good, not as bad as foundation issues that water can lead to, but it is not good.   

Hints:  Take a very close look at the attic spaces or basement (structure seems sturdy with little "why did they put this beam or support here, it seems odd".  

Hello all, I am currently in design stage of a flip and I’m looking for a recommendation on a structural engineer who can engineer a beam to replace a load bearing wall.