I have some web design skills (I'm an engineer, so easy to learn new programming languages) and I'm currently testing my new system to manage the tenants.

Take for instance an “A” located 1 +1 duplex where units rent for $2,000/m and compare the building to an identically designed “C” located 1+1 duplex in the same market where units rent for $1,200/m.

Therefore it's quite normal for a design change to be an additional service fee. 

Studying for and receiving the CCIM designation will be a solid plus.  

Bitcoin was designed to have a maximum number of coins.

Another thought you could just keep the tri-plex and gift them the net income each year...it's basically the same thing without any transferring. 

Not essential but I've used it for other things and it's really cool when you are building out a new process, design, or work flow with your team as well.  

Stores like Home Depot or Ace will have products specifically designed for removing difficult adhesives, but you can also DIY with household products.

I don't know much more specifically so ask your CPA about gift taxes (I think she could give you $17k of gift money a year without taxes) or capital gains taxes if/when you want to sell. 

Non-profit or not, it will be UW as a business...the non-profit designation doesn't eliminate the lending review, just makes the proceeds non-taxable in order to be put to charitable use.