And how easy is it to lease a 30x50 shop vs. two mobile home lots?

Rates have been skyrocketing pretty much every week so don't be surprised.The ultimate remedy is shopping at least 2 more lenders and get the best quote.

Because my input is that you should not be wrapped up in this deal, you cannot afford this house.If a lender tells you that "you can afford" $375k for your primary residence, you should be shopping for homes in the $275k-$300k range.What you've done here is maxed out your debt-to-income ratio to the point where just a small spike in interest rates has caused you to not be able to afford the monthly payment.

We are looking at heading back to the states (I'm American, and my wife is Korean) in 1 1/2-2 years.

Rates seemed to be a bit higher than a SFH when I was shopping around for mine.

I'm an insurance broker and I shop with 30 A rated insurance carriers for the best rate. 

I would suggest applying at other body shops or consider asking your boss for a raise.I had a friend years ago that worked at a body shop.

,I am thinking people will start saying you have to buy a house it is the American Dream and you won't be able to afford a house, in San Diego.  

It's a lot scarier shopping around for a first house than shopping around for my first boom box when I was a kid.  

There's many companies in southern California that are one stop shops where they have architects, engineers, etc. if you do a search.