I'm a MF broker working in the 2-20 unit space.

Here are some top-rated floor plan apps that meet your criteria and might work better for your needs:1.

if so do you just connect them and see if they ok to rent it and share the common spaces?

With your background in architectural design, you're already ahead of the game in understanding spaces and their potential!

You'll have far less competition as you move into the 5+ unit space where the different financing and higher prices weed out many of the first time investors feeding on $400k fourplexes. 

Roofs, windows, doors, flooring, appliances etc., these things have use spans and as time passes the expenses come home to roost.

That might be especially attractive to folks who want to shed the clothes they wear at work to keep their living space more clean.

Unless you have experience in the MTR space, or want to invest your time into learning, you are better off renting to a long term tenants.

That would be a foundation issue to make sure the current foundation is able to hold two more floors on top and also a height issue for the town for the area.

After doing quite well in the CT market space, I’m finally starting to adjust to the Ca market.I think it’s key to be in the know about off market deals, for both your primary and investment.