I found a cheapy Schwinn Varsity (New Model 2014 not the 70s model). The seller claims he "converted to tubeless"..Is that possible? I'm dubious since usually bikes are marketed specifically as ",Tubeless ready." Right?
Your post title and post don't seem to match up.
No, not all bicycle wheels can be converted to tubeless -- because no one makes tubeless tires in some of the sizes, like 27" and probably others. But that doesn't seem to be what you are asking. You seem to be asking if it is possible to convert a generic set of 2014 Varsity wheels to tubeless, and I think those are just regular 700c wheels, so that should be possible. All that said,
bikes aren't marketed as "tubeless ready", wheels and tires are. The bike doesn't care what the heck tires you mount. And as noted previously, standard clincher rims can be taped-up to work with tubeless tires, as long as the appropriate-size tires are available. Whether or not using important parts in a manner not recommended by the manufacturer exceeds your comfort level, is something only you can answer.