@Brad Johnson, as mentioned by @Brenden Mitchum and @Jonathan Greene there are real dangers of developing discord when working informally with friends and family.   

Not only is that a useless number, it's dangerous when people rely on it.This is something that we Realtors have to struggle to overcome. 

The danger in using your own personal standards when rehabbing is that you may have higher standards than others in the neighborhood, and you'll end up spending money on the rehab that doesn't pay for itself.One thing I've heard around the campfire is that appraisers have different methodologies in different farm areas. 

It's only dangerous in dust form.

Compliance is nearly impossible, failure to comply is punitive, the seller gets fewer protections, and the buyer can record ON THEIR OWN the day after signing (attempts to restrict this in the docs are void on the face).Besides, if/when the buyer takes the seller to court, no guru will be standing beside you. 

Understood, it is common to have deals which are difficult to comp but the whole point here is that you need to find some other pros to help lock in that exit value number a bit better, like I said, if it is $520k or better, you have enough room in the deal (in my opinion) to move forward with the terms you have laid out, if below that, it is (or can be) dangerous. 

I love multi-family properties due to fewer closings and paperwork.

You’re not going to have enough profits, split 4 ways, to make use of the small advanatage of SCorp status to reduce self employment taxes.First and foremost, flipping is a Very competitive endeavor with Everyone wanting to do it....hence, fewer opportunities and slimmer margins.  

The higher quality the tenant base (documented income 3x+ total rent, solid employment history, no eviction history and clean criminal record for past 7 years), the fewer issues you’ll have renting or selling the homes.  

It has newbies thinking they can play investor and get into a property without any of their own money which is not only foolish .. but dangerous