It’s sort of the equivalent of saying we don’t really want to be in that business but for the right price...  

Cash is the ultimate liquid asset.and(things that can be converted to cash--constantly quick)Treasury bills and treasury bonds.Certificates of deposit.Bonds.Stocks.Exchange traded funds (ETFs).Mutual funds.Money market funds.Thinking otherwise could be useful (personally), but "Liquid Asset" is a defined thing.Like a steel I-Beam is a defined thing vs a 2x4 (another defined thing), an I beam could be 2" x 4" but most would spec a Steel I-Beam vs calling it just a 2x4.https://www.wallstreetprep.com/knowledge/cash-equivalents/Is this the Creativity of a top Architect bouncing against the rigidity of Accounting definitions.

There's no equivalent of the furnace, there's no decision to go radiant or electric or forced hot air, etc… It's just adding a meter and running wires.

A guaranteed, after-tax return of 7-8% (the equivalent of earning an ~11% return pre-tax) is about as good as it gets. 

A deed of trust is equivalent to a mortgage.

As for the transfer, yes - you should have the entity "buy" it from you with you conveying a warranty deed (or it's equivalent in a non-judicial state).

For every $500/month increase in NOI on forced appreciation, it's equivalent to $100k in equity in MY market. $50/month rent increase on a 10-unit bldg = $100k in gained equity.

They currently have just enough income from pensions (401(k) equivalent and the state pension) to live.

If you're okay with that, and taking the long view, then yeah, you'll have a hard time getting into an equivalent investment vehicle for less money down.But less money down isn't always a good thing, especially depending on what you're buying.There are many reasons why moving up to larger multifamily properties makes sense, but one I'll point out here that's worth considering lies in how properties are valued.Your quad is based on comparables, which means it's worth pretty much exactly what all the other similar quads in the area of your property are worth. 

What you're asking is basically the equivalent of cancelling a landlord because you don't like the rental or the landlord.