Hopefully 9 months to 1 year notice but sometimes it is 6 months to 3 months.If it is a good area with a reasonable box size then usually a bunch of tenants with expansion plans to take the spot.

1) It is not yet clear but it seems that you will be grandfathered in at the time when the changes occur in regards to occupancy changes.2) Per AB-68:"(A) One accessory dwelling unit and one junior accessory dwelling unit per lot with a proposed or existing single-family dwelling if all of the following apply:(i) The accessory dwelling unit or junior accessory dwelling unit is within the proposed space of a single-family dwelling or existing space of a single-family dwelling or accessory structure and may include an expansion of not more than 150 square feet beyond the same physical dimensions as the existing accessory structure.

Congratulation of your expansion.

Most student loan reform is expansive and not limiting.

Some areas like Reston and Tysons corner along the silver line expansion still have some good deals.

Has a lot of expansion happening (not just Amazon HQ2).

While it's better than having really expansive soil, you'd probably have to get the place for very cheap for that to be worth the effort. 

All economic signals are pointing in the right direction too, more jobs, more business expansion, great schools AND low cost of living.

First - congrats on the expansion of your portfolio - BP is an awesome resource.The answer to your question really depends on how you set up your business structure - LLC, S-Corp, etc. - are there preferred returns listed in there ----- assuming these are equity investors and not debt (i.e. they have mortgages against the properties). 

Located next to a well known local university and close to another, the expansion in this area is tremendous.