If you are going to update it, I would replace the windows and sliding glass doors.

Neighborhood is mix of rental and single family, with SF homes showing strong appreciation.Given all this, if you wanted $100/door, what would you pay for this duplex?

Sheetrocking over old lead paint would rarely be an economical solution if the room has doors, windows and trim....which most do.  

A home can sit and sit and sit and sit, until the seller either make more improvements which they usually never ever do or drop the price.

One room at a time, one wall, a bathroom can go quickly. 

I'm sorry to here about your career change, but sometimes when one door closes, another one opens right?

Say you had a four bedroom, wouldn't there be some sort of "manager" you would have to put in place considering all the shared rooms, ie kitchen bathroom living room etc.

I have used a company called 40 offset based in chicagoland they charged about 300$ for 1,000 6x4in full color two sides to the door I just supplied them the list.

Hello BP, while i'm looking through different online offers to get a better pictures of the multifamily investment, i notice in my area there is a lot of 2-2 & 3-2 bedroom bathroom.For now, my plan is to invest in 2-1 unit only to young & old couple (for the sake of argument), what can i do with the extra said bedroom &/or bathroom

An example would be decking under shingles, or subfloor under bathroom tile.