Tertiary markets can be cash flow heavy but tenant/asset risk exists.

This eliminates the requirement for a new down payment since you are refinancing the existing debt.Lenders typically require:A copy of the owner-financing agreement.Proof of on-time payments (6–12 months).What to Do:Find lenders that offer rate-and-term refinancing for owner-financed properties (portfolio lenders and DSCR lenders often do this).Maintain a clean payment history.” 

Question 2: Where can I find state or city regulations regarding tree maintenance when the lease is written with gray areas?

I am debating about the converting the existing old gutted building to either multifamily building (6 units each around 500 sqft small studio) or mix of 4 residential and 2 retail/restaurant conversion (the back side of the property has Big enough lot for outdoor dining or any other use cases.Any recommendations for use case of pure multifamily or mixed of multi family and retail?

The market is priced too high to buy existing locations in my mind.  

Sadly the property no longer exists; it was at 22 Riverbend Drive sitting on the Swannanoa River, and like all nine houses sitting on the river, it was swept away and floated down the river.

Be aware of any local regulations in Emeryville as well.Please make sure your 4plex isn't exempt from AB 1482.

I haven't seen any yet that do 10% down on non-owner occupant purchases, but that is awesome if that exists. 

Your definition is correct for "legal non-conforming".The "legal" part of "non-conforming" is dropped when it doesn't apply so most commonly people call these units "non-conforming", "finished", "in-law suite/unit", or "bonus unit".Non-conforming: Any property that doesn't meet current zoning requirements.Legal non-conforming: A non-conforming property that was lawfully established under previous zoning regulations and is allowed to continue its use.Based on his posts @Mario Morales is referring to a non-conforming unit.

Use some for buy and hold (I personally would prefer apartments rather than buying a few single family homes) and some for lending/trust deed investing.In either category, you must know what you are doing, know how to vet the investment, how to vet the sponsor (if investing in a larger fund of some sort), the laws and regulations on the lending side, how to investigate which areas to invest in buy and hold and notes/trust deeds for that matter.So as you have already said several times, lots to think about . . .