I'm a developer - buy, entitle, permit, finance, build, operate larger projects - but regularly have to deal with the same thing you're asking about - how can I fairly compensate someone for their contribution to a project? 

I paid for drawings, survey and waited two months as  I applied for permits, only to find out that two units on my parcel would be over the limit per acreage.  

Also permitting would pretty much force your hand.

We did a lot of the work ourselves but it still cost about 30k since we hired professionals for permit work and replaced appliances.

So, I would treat the deal as if the seller is striving in every way possible to rip me off, and I would verify EVERYTHING; I would go to city and check on all building permits vs what there, rental licensing, zoning, I mean literally everything I would leave nothing to chance what so ever. 

Due to permit issues if you can believe that it’s been a year.

I’m in Philadelphia, PA and was wondering if I needed a permit for a washing machine/dryer hookup in one of my apartments?

Fannie Mae and Freddie Mac both are still permitting 75% of the ARV or your purchase price, whichever is lower, for "Delayed Financing" transactions. 

While you can do most of the work yourself, you will need a little help from a licensed electrician and plumber to pull permits and pass inspection.

Several months ago I asked for recommendations, and BiggerPockets removed my post, telling me they don't permit solicitation in forums.