I guess every land surveyor will come across a situation like this one. I think this is the absolute worst one I have ever seen.
Some background..
The structures date from 1923 - 1940. The client is a trustee of the estate which comprises Parcels A, B and C. He is remodeling all of the structures with, I suppose, the intention of selling each one after everything is done. He told me that the city and the tax assessors off has fouled up the addresses because PCL B has an address that is within two numbers of the house fronting on the avenue on the east, North is up screen. PCL B does have a mailing address that coincides with the street it is fronting on that runs East/West. I know that the city has knowledge of what the situation is with PCL B and C, but as the norm is, they never seem to actually help the public out, they just want to be left alone. The assessors is also probably aware of the situation also. It's funny how most people never see the red flag that pops up.
Since PCL C overlaps the lot line it has tied PCL B into one lot, so now there are just two lots that may be sold. However, the negatives of that is that the two story structure on PCL B is only within a few inches of the west lot line. The ultimate RW for the North/South Avenue on the East is 80 feet. R/W takes have been done North and South of PCL C, so there is a future take that will be done on PCL C, bt whatever means, but it will happen. This will create a sub standard PCL C after this takes place.
A lot line adjustment for any of the parcels is out of the question entirely because of specific zoning regulations.
I have not told him what the situation is. I would rather just hand him the final maps and collect my fee.

Looks like time for a re-plat.
And around here, the name associated with a street address at a corner parcel is determined by the longer frontage.
Let me clarify:
It looks like time for a re-plat with some obvious setback variances.
Paul - What did he hire you to do? A site plan for his remodels or a boundary survey or what? I see that B & C can't be sold separately because the C building is over the line, but is there a problem selling B&C together and A separately? Since you say zoning won't allow boundary adjustments, I assume that's because of net lot area requirements?
What is it that you think the problem is that the City should deal with? Are they hassling him on his remodel permits because of the existing non-conformity with setbacks and such or is it the addressing that's hanging things up?
If the situation existed for more than 5 or 10 yrs and there were no public nusiance complaints, the muni has no basis for a complaint.
Replat with a variance request.
Cite your applicable state law.
Who else but a surveyor could correct the mess?
Richard Schaut
Do a one lot parcel map for condominium purposes (3 airspace units). Lot one common area with three separate condo buildings.