In my primary I have two tenants living in separate building structure. you could still cash flow in bay area if you have SF with 5-6 BR or have multiple building structure.

I've gotten a couple quotes and and it's around $350K to add an ADU for any investor (separate detached unit on same lot).

Assuming this is an investment property, keeping track of your expenses and income in a separate bank account (not personal) and ideally holding the property in an LLC 

I will have access to ~1M in cash for down payment and closing costs (I would also have reserves, separate from this capital).

Do you factor it in the monthly rent or do you charge the guest who is basically a short term tenant separately?

The path I've chosen is to keep equities and real estate separate. 

If we then have another meeting that we are pre signed up  and have paid for which is on Wednesday, the expenses that my wife and I incur on Tuesday are deductible because it is considered a work day since it falls in between 2 separate days of meetings that are directly related to our business.  

I've done this with my properties because I'm well known in my small town and don't want people to know what I own.LEGAL PROTECTION: By placing your assets in an LLC, you are legally separating them from your personal assets.

On separate properties, if you're eligible, then yes. 

Tell them the gym will be in your unit with a separate entrance where you could control the hours it was open.