You need to count all costs.

I have two properties in Marco Island (Which are doing very well BTW, even with high expenses, and I also count on appreciation and since it’s an island, will always have some attraction).  

Smart buyers understand the value of a Buyer's agent and it certainly is not just to open doors.  95% of my clients are out of state investors purchasing in a market that they do not know nor live in, they count on me to walk the property, access repairs, provide comps and short term rental numbers, arrange and be present for inspections, as well as my ability to assist them getting their short term rental set up for them long distance.  

Any property acquired this way counts as one of their identified properties for purposes of the 3-property rule

Normally, for comparables, you want to look up recently sold properties within a half mile to a mile (the closer the better), in similar condition, square footage, amendities as the end product, and the same or similar bedroom/bathroom count.

& you'd all have to personally guarantee anyway. only have the mortgage would count against your DTI if you have a 50/50 split.- what if your parents alone get the loan and buy the property, then quit claim deed it to a trust with all 3 of you as beneficiaries. the trust would have a jv / operating agreement outlining everyones percentages and responsibilities. the debt would only be in their name.- every investor reaches a point where their DTI is trashed and they have to move into different loan products. there are tons of lenders out there that specifically work with REIs & have many ways to navigate this. don't let DTI concerns keep you from moving forward. - LLCs provide minimal legal protection in case of an incident. work with an asset protection attorney to come up with a better plan if they are that concerned. also have great insurance and an umbrella policy. 

That will count towards his experience.

What is the best configuration (bed/bath count, building type, etc) in your area and for your target clientele?

Most people here would count that as 10 doors.

If we turn the tables and say it could be a 95% failure ratio. ( doubt it's ever that high but just for conversation sake) In general for the whole country if we count everyone.