. $40k will not get you a non owner occupied San Diego property unless you find some unlikely alternate financing.

I know that the general guidance is that emergency funds aren't to be invested, but given our financial security and the fact that we already have a personal e-fund in a safe, non-volatile location, would it still be crazy/unwise to invest this 15k in an S&P500 index fund in a brokerage? 

One thing to be aware of is the FHA multifamily self-sufficiency calculation which determines if a property can generate enough rental income to cover its mortgage payments.

When I told him it would be a very bad time to sell the mortgage notes as there were almost no buyers, he said he didn’t realize we were investing in non liquid assets?  

I have enough liquid money for the down payment for the hard money lender, but that'll leave me with zero cash for closing costs, realtor fees, etc.

Can try to reposition to Class B, but neighborhood may impede these efforts.Vacancy Est: Historically 10%, but 15-20% should be used to also cover tenant nonpayment, eviction costs & damages.Tenant Pool: majority will have FICO scores of 560-620 (approaching 22% probability of default), many blemishes, but should have no evictions in last 2 years.

Current value of paid off property is roughly 350k , looking to borrow 75k-100k down payment to  purchase a 275k commercial property.

Again, I'm in Portland Oregon, and they specify "tenant applicant" (paying for rent) and "non-tenant applicant" (not paying).

Lastly, ADUs are allowed for NON owner occupied properties, opening this strategy up for investors who could convert a SF into two units. 

For the experienced cohosts in the group, I’d love to get your thoughts on payment processing options for cohosting companies (LLCs) that position themselves as property management companies but operate without a broker’s license.As an investor and soon-to-be STR entrepreneur, my business will initially focus on managing a small portfolio of vacation rentals with plans to scale.