Multi-Family Appraisal questions - two unique situations

[Nicholas B.]

I have an 18 unit multi-family property that has rents that are roughly two to three times higher than the neighborhood comps. My 300 sq ft studios rent for $600 and the property across the street gets $700 for 1000 sq ft 2 bedrooms. I can show a rental history on my property going back two years with those rents.

How does an appraiser view my rental prices for the purposes of a loan? 

Lets say I build 75 units on this site that get those rent amounts, does that change anything? 

And here's another more interesting question. This multi-family is on two acres of land zoned for 75 units. The land currently is worth roughly 1 million. The rental income currently is 150k gross and 120k after expenses. 

Highest and best use I'm assuming is the current use. at a 6% cap rate it's worth 2 million. However that doesn't give any value to the land value. 

If you appraise it purely for the value of the current income you're completely discounting the land that's included in the sale. If you appraise it for the land you're ignoring the value of the rental income. 

I also can't think of a way to combine both of these. As an investor I'd pay 2 million plus an additional amount for the potential of development. Does an appraiser look at it this way too? Or simply value it at 2 million?