Good intentions, but unrealistic.
If you're building a car for the masses, particularly a 4 door sedan, with economy in mind, it's going to have to be a FWD. There's a dual benefit to FWD, it reduces the cost of production (no driveshaft, less moving parts) and increases interior volume (no transmission/driveshaft tunnel). These are key features in building an inexpensive car for the masses.
Interior space is just as important as cost. When thinking about a small car, the last thing to pop up is interior room. It's kind of a paradox. But auto manufacturers place a lot of emphasis to make the most roomiest car in it's respective class as possible. Interior requirements affect the layout and exterior design of a vehicle which is why you see most of the small to mid-size cars for the mass market FWD. This is also the reason for the "ugly" bubble look. The larger the platform, the more you can stretch it out. thsi is why the "classic" styling with a smaller car would be more difficult to achieve.
4 door with a coupe offshoot are very likely.
4 cyl and turbo 4 are very likely. 6 cyl is not as likely, but still realistic.
I think the new Dart will be around 3,000 lbs. So very possible.
So the new Dart is not too far off the mark with your requirements. I think the biggest issue would be styling...yeah, it won't look like a baby Roadrunner. But from the looks of it, it will probably take some front end and rear end cues from the Charger. So in a way, there is some relationship with the rest of the Dodge lineup.
I don't know how successful the new Dart will be. Their really going up against a tought market which is probably why they are building it off the Alfa platform to save costs. IMO, I don't feel that the use of the Dart badge here is any different than what was done with the Charger. That's just me though, so take it for what it's worth.