Some engineered wood floors can be installed below grade and have instructions on properly doing that. Since floating floors are engineered (mostly) and are designed to be installed over a plastic vapor barrier and a foam pad, that "handyman know nothing" from Boston was incorrect. Google Kahrs and go to their website. Kahrs makes nice floating floors and some can be installed in a dry basement. Installation instructions are on their site as well.

Was wondering about that "underage" thing in your post too, lol.
But more to the point, Almost all engineered wood products would be acceptable in a below grade application.
Even if you had the headspace, solid wood would not be recommended, even over a sub-floor system as you suggested. Most of the floor issues in basement applications are caused by accumulation of humidity in the air. Raising the floor a couple inches is not the solution. We have (under duress, and with signed waivers from the client) installed solid floors in basements, but the home-owner must run a dehumidifier hooked up to the storm drains, constantly. Even that does not prevent possible issues.
Floating an engineered hardwood over a pad with vapour barrier attached is your best option.

Dri-cor has its uses, but Im not a fan. Mostly because of the exaggerated claims of increased comfort level. It does increase air flow under the floor system but to no great degree. We have actually installed powered vents into the sub-floor at opposite ends of the space using slim line fans mounted so that at one end they suck, and at the other they blow. Not meant as some kinda joke, lol.