The big deal was you could shift while coasting.

https://www.flickr.com/photos/20121327@N00/510257722/

You could convert it but it probably wouldn't be worth the expense to do so. The front crank should come out like any other 1 piece crank. I have one on the shelf at work that I removed so it can't be anything hard to do. I'd just lube things up and see if it works then sell the thing and keep looking for something better.

I have had a few bikes with positron and they seemed to work okay. The FFS system is weird, but works.

With the FFS setup the rear cluster does not spin, if I remember the bikes I have had with that setup. So, if you pedal the bike forward does it not move? With the FFS crank, you can coast and pedal backwards, right? If, so, what is the problem with using the bike?

Oh, and I don't think $60 is too much for a Varsity. It is a piece of American history and is a great campus bike. Tough and not a magnet for thieves.

Now that we've established it's a Front Freewheel, is there anything wrong that still needs fixing ?

Well, I'm not sure how to disassemble the front free-wheel; the crank came apart easily enough, but I want to take the FFS apart as well to clean and re-grease the bearings.

I'm also still not sure; provided I wanted to convert it to single speed, would I have to buy some special rear cog or would any aftermarket thing on amazon work? After hearing that the rear cogs need a special tool that isn't the typical Shimano to take them off, I'm concerned about their compatibility with standard bike technology.

I would not attempt to take the freewheel mechanism apart. Wash it out with some solvent or spray (WD40) and drip some light oil in there after it drys and you'll most likely be good to go.

Yeah, I get that part, but the freewheeling chainwheel should acommodate that with a fixed cassette. It's the independant cogs I don't get.

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Well, you could convert it to single speed by eliminating the derailleur and shortening the chain. I would run it on the small chainring and the second-smallest cog, with 17 teeth. That's kind of low geared, and the chain angle is extreme, but it'll work.

Note that this won't be a "fixed" gear. You'll still be able to coast, and you should keep both caliper brakes in good working order.

Converting it to a more-conventional non-freewheeling chainwheel and single cog (fixed or freewheeling) is possible, but much more involved.