Also, seems like a red flag to me if the agent is telling you he can get the current tenant to sign another lease if you buy the property.

Run the numbers, you're in the red.

I would like to chase more of that business but I want to see what you feel would be an appropriate rate to pay per square foot.

@Dave Skow does washing Appraisals hobby the conditions of the property like California or more off the square foot like in the south ?

You'll never be out of the red. 

UPSTAIRS:  fashion styling retailer M2M, psychiatric office 1 year, OPEN SPACES: 1000 square foot, 5 rooms with receptions area (old dental office), small little single door office (200sq ft), Open space 500sq ft room, electrically fitted for culinary cook kitchen, but could be used for anything. 

This property will very much be in the red as a rental.

Any way you look at it, the cost to build an ADU is cheaper than the cost per square foot it costs to buy any existing property in LA (SFR, duplex, etc) plus you get brand new built space rather than on the 'old' space of an existing property. 

So things that are a red flag for me may be fine for someone more aggressive.

Info  Retail building, two stories 4893 rentable square f. 2393 square f. rented to a kindergarten (8.36$/sf is the lease) or 20k a year. 2500 square f. vacant. could be rented at 18$/sf - net.