That will show what proposed tax increase you will see.

I would recommend an STR for the best tax benefits and cash flow no doubt.

Lower taxes, no POS and lead testing. 

If you paid under $230k, you’d save $30k in federal capital gains taxes and maybe another $15k or more in state income taxes.

I have 2 options:- finance the construction pre-selling the apt, and take my profits (expected to be around 700K pre-tax); or- finance the construction with a 6-7%/year loan (collateral = my house), keep the 10 units, and once the building is completed in 24 months, rent them for circa 180K/ year gross.

Is it better to get an LLC when I become a land lord to get some tax benefits?

Have also used list source and prop stream before but the data they provide is very similar to what I pull off the tax records through CRS Tax. 

@Andrey ShostakA tax calculator would be nice.

Finally, even as the landlords cash flow increases, depreciation should keep a major portion tax deferred. 

If you need financial help, ask under the "Finance, Tax, and Legal" forum.