So scarify 6" to let it dry, compact, scarify again as needed, etc. 

Will it only be for a lower class because of affordability or will there be a market for compact affordable electric cars.Which begs this question...Would you buy a gas station, jiffy lube or any other commercial property that caters to petroleum based cars?

Make sure you budget for time, consultations, removal, root raking, in-fill, soil testing, compaction testing, and tree replacement costs. 

Purchase price: $196 Cash invested: $50,000 A compact two-family house with one 1 bed/1 bath apartment and one 2 bed/2 bath apartment and a small backyard.

Could I alter the proceeds proportions? 

Was it compacted?

Debris must be compacted and fill dirt must be compacted,  you don't want a sinkhole in your yard. 

@Jeff Cliff if it is an in ground pool this is not the job for a handyman and will likely cost $5-7k because you need to make sure you break up the bottom of the pool to ensure proper drainage, demolish the decking and fill compactly. 

All work at cost paid for bth the contractor and splits profits parí passu meaning proportional to the value of the work. 

Finally, use Nathan's proportion to estimate the rent increase (including the "overage" cushion he suggests) above market for each unit.It's a bit of work, but not unwieldy, and it will give you a closer approximation than a total guess that will need to be adjusted in the first few years of service.