This would all depend on finding the deals though, as that is the hardest part.

Depending on the market if you did that with all quadplexes you could be at 16 doors in 4 years (not including traditional investment properties you may have aquIred) with a total of $0 in downpayments its an under used loophole in the system.

for me its usually depending upon the situation.......u kinda got to feel them out and see if theres an underlying issue at hand....but yea never more than 3 business days......but you can tell whos stalling. 

Depends.

It depends on the realtor.

I think each neighborhood works independently from each other, depending on the different criteria that buyers choose.

Depends.

Sure, you can make more money in real estate in the more boots on the ground fashion, but it sounds like you'd be much better off looking for truly passive forms of investing as recommended above.

It depends on a few variables.

You are both entitled to your full entitlement amount (somewhere around $400k+ depending on the area) and you can reuse it or have multiple loans at a time up to that value as long as each is your primary residence for a year.