Bike terminology is fairly precise, and when you say freehub it is way different from freewheel. Since you are admittedly new to this, you might benefit from checking out sheldonbrown.com and searching for information on fixed gear and single speed bikes. There's a lot of very practical information on how to set up your bike, what gearing is appropriate and other good stuff.

Regarding handlebars, the reason there's so many options is because folks seem to be always on the lookout for the "perfect" bar. I don't know that one exists, but if it did, it wouldn't be perfect forever because as we age, many of us have difficulty with drop bars. And so we begin with shallow drops, taller stems and eventually make the jump to flat bars, moustache bars, riser bars, whatever.

You say you like the look of drops and you mention track bars, which are a form of drop bars. Form matters for most of us, but function is arguably more important. Just like the people searching for "perfect" bars, it seems there are fads that come around. Avoid them, unless you like to spend money and do it repeatedly.

Ride the flat bars long enough to decide whether they are comfortable or not. Only then would I change things up. Use the money saved to buy something else for your ride, such as upgrading the wheels or something.