You're kind of jumping all over the place now. Originally you wanted a classic looking steel frame and not an Aventon type. The Crew District is very similar to an Aventon style aluminum frame. Even on City Grounds they list comparable frames and mention multiple Aventon models.
Crew Bike Co. District Track Frame 2016 | City Grounds
You're also going to need to buy a fork....most likely an Aventon model.

Not a huge deal but also remember that raw aluminum won't look like classic chrome you would find on a steel bike. Just a heads up.

AS for the Unknown, which model are you referring to? Again, I think they're all aluminum and similar style to an Aventon.

Scrodzilla will be able to shed more information on these companies since he knows the industry. There are so many new companies (almost always from Los Angeles) making similar aluminum Aventon style track bikes that I'm sure many of them are the exact same model but with different stickers. He'll be able to tell you what's decent and what's garbage.

Personally I would stick with a nice traditional steel track frame.