The upper dwelling would have three bedrooms and two bathrooms.

I'm working on projects in florida and ohio. entitled or unentitled is a big difference. we typically look for land in larger tracts in columbus ohio for under 50k per acre. that's mostly rural land that is then entitled through engineering and zoning variances, a huge money maker if you don't do it. entitled land depends on density. lowest I've seen is typically 6 dwelling units per acre and highest I've seen in suburban markets might be 26. i think there is a lot of missing things to answer your questions like how big of projects, but I can give you a very recent lot we featured for investors who build a stacked triplex with us around Orlando and other markets in florida. it was a 43k piece of land on about .3 acres. through planned development you can get a duplex approved it was in poinciana in Osceola county. that's on the small side and it's hard to find land and it wouldn't really increase in value there but that's about 5k or less in fees to get that done. so all in 50k for a 2-3 unit. so 25k a door would be a good price to look at. normally as you buy at scale it gets much cheaper because you are doing all the value and creating something from rural land or wetlands, etc. entitled land typically sells for 11k-13k per door I would say on average in suburban markets on a national average. that is extremely difficult to track but we work with groups in land entitlement all over the country who co -develop with us and we create benchmarks that's more of an internal conservative and we push high density and multifamily to maximize profits on the exit once the project is entitled. 

Here in milwaukee, you cant pull a building permit unless you have a contractor’s license which requires a state single family dwelling contractor’s license which requires a bond or insurance.

We are looking for 15 dwelling units to 25 dwelling units per acre in a suburban area.

Is any land dedicated to specific residential dwelling?

Quote from @Pandu Chimata: Quote from @Dan Heuschele: Normal state rules would limit ADU to 50% of current dwelling.  

This strategy starts to compound when you find homes that have an ADU (accessory dwelling unit, casita, bungalow, etc…) along with the main house.

FYI, State Farm, at least here, uses a percentage of the dwelling coverage as the deductible amount.

High density is 40+ dwelling units per acre.

Umbrella insurance (beyond the liability insurance for each rental dwelling) is far less.