They will also be able to gather any information you would need to make a good financial decision.

You wouldn't  happen to have the contact information for that gathering  would you?

Google searches are not that helpful in providing accurate reviews and most of those look negative .. so hopefully if someone's currently using a mgmt company it will be better to get first hand info :)

I believe an FHA loan requires you occupy the property for at least 12 months. while you need to double check this, if accurate, it means at month 13 you could buy another place, FHA insured at 5% down, and pick up a second property. that is a strategy you could implement over a number of years if the math works. as for a multi-fam that allows you occupy one unit, vs. single fam house or even condo, it just comes down to math. there is nothing wrong with having a friend or random occupant rent a bedroom from you, as long as the rent reflects fair market value (so I don't agree that charging a friend rent "could strain the relationship" - unless you're over charging of course). beyond all that, it is absolutely critical, obviously, that you screen your tenant / roommate rigorously - and living with "friends" isn't always a good idea. create an excel spreadsheet of these three verticals, any others I may have missed, with math predicated on what your local market reflects and feedback from lenders and see what it looks like. 

Back in the prehistoric days (80's and 90's) when I was a listing agent, we were able to gather all manner of information regarding a buyers loan qualifications but times have changed. 

My idea is i am looking to gather more than 10 small investors like me who like to do the business in Baltimore city, and all of us buy all the properties in one street and rehab them at once, so in this case the value of the properties in that street will boom up and the small investors get their profit.

@Philippe: Thanks, I'll take your suggestions and spend more time accurately estimating those expenses.

I am wondering if there are any websites the BP community uses that give accurate numbers such as;Average rent for your areaAverage PMI for your areaAverage electricity billAverage water, sewer, and garbageand so on....I have used a few websites that seem to give me accurate numbers but I would like to know if there are any better sites out there.  

Also how accurate is your ARV and Reno costs

I can do basic evaluations without MLS access, but would like to get a more accurate ARV.