I am semi-retired now and want to move to Seattle, but can't get a pre-approved loan from Wells Fargo because I don't have enough income now, any suggestions to get a loan pre-approved from Seattle local bank or mortgage institution? 

Look for BPI (building performance institute) or RESNET certified individuals or companies.

I find that the hedge fund institutional investors are gone so I see opportunity.

Doing business with a commercial loan lender.If you are using an institutional lender then why can't you get a generic pre-approval from them?

They are 30 year loans from an impersonal institution who has really low historical rates.

(I typically don't do take this route because I do a lot of work myself...which I cannot write off since I am not a general contractor).2) The financial institution will order a second appraisal.

NNN investing is based on credit of the tenant and strength of the lease along with location.REIT's ,institutions, private funds love NNN properties.

Family is the most important institution.

Call around to your local banks and lending institutions.  

There is heavy institutional investing in the area and it is tough finding deals there in general.