For the other unit look and see what is common in your area. 

It seems that DTI is a common obstacle with such loans.  

It is very common to have to only a husband or wife working.

Examples being common things that take place with tenant turnover or larger expenses like a new AC or roof?

The big money is in 4+ units where you increase the rents and the rent increase automatically increases the Cap Rate and the property's re-sale value.I would like to see more people pushing people to understand the power of multi-units and the very strange thing is that I skim through every real estate book I can get my hands on and every book I ever read is missing the very most important facets of multi-unit investing and every book is full of pure B.S. when it comes to the subjects to the pitfalls of multi-unit investing.

@Fabian G.Happens all the time here, your Realtor (if you used one) should have educated you on the pipes.However in this hot market it’s very common for buyers to move forward with the piping as is.I imagine it will be difficult and expensive to hold your inspector accountable so it would probably be best to negotiate with the buyer or find a buyer who doesn’t care.I recently sold a unit to a buyer whom I warned about the potential issues and he simply didn’t care and moved forward with the transaction.

Some common pain points are:Seller needs cashThe seller is managing the property from another stateSeller inherited the propertySeller wants to switch his/her line of businessThis being said, there are a few basic questions that you can ask to easily dig out the pain point.

10% is common for your balance sheet and signing on the loan.

It's up to you to choose one.The most common methods are:county assessmentprofessional appraisallocal Realtor's opinioncomparable sales of undeveloped land in the areaYou can also choose whether you apply the $ number or the land/improvements ratio.

Curious if you would also be interested in package/portfolio deals, those are a lot more common in Philadelphia and the suburbs then stand alone 10-20 unit multis.