Which of these areas would be a better play for house-hacking in terms of likely appreciation over the years and rentability to potential tenants?

A general guideline of a certain amount per square foot might be nice for planning, but I would never use that number when I have a potential property identified.

Our company is looking to jump into SFR investments and want to look for properties in the OC area with value-add potential to either rehab or add an ADU/convert a detached structure to an ADU. 

There are many different ways to find potential hosts to co-host for.

I've flirted with the idea of a townhome / condo but don't feel they have the same long-term potential...  

It's a vibrant market with diversified communities and promising growth potential.

I’d advise you speak to a CPA as well, different trusts bring along potentially different income tax filing results.The maxmimum income tax rates on trusts are also reached far earlier than they would be on a personal income tax return.Generally trusts and LLCs serve different purposes as well (i.e.

No problem buying one for myself, but as a business decision I operate out of those or really natural disaster risk zones. 

Will depend on several factors like the type of property, type of tenants, your risk tolerance, other assets you own, your estate planning, laws where the property is located, etc.

Factors such as higher interest rates, taxes, and insurance can significantly impact potential returns for investors.Remember, success in real estate investment often hinges on buying properties at the right price rather than selling them.