There's something to be said for being able to try a bike out first. The Redline is a good bike for the money. Of your list, I'd go with the Redline.
The Volume is more designed with casual cruisin' in mind. As such I'd suspect it to be a bit sluggish on the track.
The General Lee really isn't too bad for the money. Full Chromoly F&F. But it DOES have the components of a sub-$300 bike. I'd expect to end up making upgrades in the future on that.
The Shadow Conspiracy is a NICE bike. Good parts, etc. But it was released three years ago w/ a limited run of 300. No longer in production. So they're gonna be a bit tricky to find. EBay would be your best bet on that.
Do you have any Trek dealers in your area? If so they can get MirraCo bike who make a 24" similar to the General Lee.
Still - I'd recommend the Redline, if your looking for a complete you can get locally. If price is no limitation, and you don't mind mail-order. You can custom build a bike. I'd go w/ S&M personally.
-Bill