Feedback Requested-Commercial Prop Down Payment & Financing

[Scarlett Mulligan]

Hi, All!
I have an office space I have been renting for 3.3 years.   I had right of first refusal written into the lease should he want to sell in the future.  

The monthly rent payment is quite low - Less than $11/sqft./yr (similar area spaces are $17-22/sqft/yr).  I would like to purchase the building:  1. to make some modifications in the building to optimize the space for business growth (adding an additional revenue stream & creating space for another support staff member)  2. prop owner is aging.  I would like to avoid potential complications of children or wife should he pass away.   The location works well for my business. 

He is willing to sell to me today well below market value ($375,000) w/ 20% down, 20 year mortgage at 5%, no points.  Area comps put property value around $425-$450,000 range.   

I do not have 20% down - will take 6 months minimum to create it. I do have an experienced REI / friend who is willing to lend the $75k but I do not want to tie up his money for longer than necessary. It is my understanding I would need to wait one year to refi the mortgage for larger than original amount.

I was considering borrowing the 20% down from the friend, closing the deal quickly,  then take out a second mortgage to pay off the hard money lender

Any other creative solutions / ideas?  Thanks!