I don’t know about 6% annual appreciation, but 3% - 4% is very doable going forward in my opinion.As you know, the SFBA is home to over 7 million people.Based on the 2013 population report from the California Department of Finance, the Bay Area is the only region in California where the rate of people migrating in from other areas in the U.S. is greater than the rate of those leaving the region.

In theory its doable, but the market is warm enough right now that they go pretty quick.  

My second is not the ideal and best choice but doable with the type of area you work with which is self installation.New hot water tanks are about $400-$900 depending on the need for the client plus any pipe adapters for the tank if needed as well as paste or tape for sealing the utility pipes. the package include instruction about installation which was not bad out of a 5 point scale of difficulties i give it a 2.5 or 3.

With equity in place lining up 75% debt is pretty doable as long as the property cash flows (meaning your acquisition can support the debt and pay you).   

This house is a little further from the medical school but definitely still doable (15 minutes rather than 5).

My friend tells me that an annual rate of return in excess of twelve percent is doable in this area.I am not an experienced real estate investor, but i have used some of my excess funds to purchase various properties in Oregon. 

I guess any future projects will look doable since you've already done a big one like this.

If you were using hard money, it might not have been doable, though.

But we have not check the zoning code if it doable.

Might be doable, but your first hurtle will be the zoning of the property and next adequate parking.