Well my first questions during my first read through (this time) of the main book are:
Should I begin planning and brainstorming for the game and learn the system with my players or will that likely be disastrous?
From my experience, learning by playing is the only good way for the DFRPG. It does help if you go through the book and make yourself a cheat sheet (or do we have one of those flying around somewhere?), so you have the important parts immediately at hand, and references to pages to quickly look something up.
In the process of getting a game together what order is the best? Do I get players before making decisions about location?
Being that the players and their stories are so integral to the game, do I begin brainstorming game directions or let them make characters first?
You will probably be better off having most things prepared beforehand for a first game, unless you are good at improvising. Yes, group city creation is one of the big features of the DFRPG, but for a new group, it can be pretty overwhelming, especially if you usually play RPGs where the GM prepares the adventures. However, the characters should be created as a group, so they fit together.
To fit the characters into the story, you can either give the players a few plot hooks ahead of time, to figure out how they could link their character to it, or you go the other way around and let the players create their characters and form the beginning of your story around it. The first method, I think is actually better, because the characters will feel more at home inside the story.
Now that doesn't mean your players can't or shouldn't contribute to what you prepared, or maybe at some point even create a little detour. In my pbp game for example, an NPC with one line of backstory suddenly had a history with one of the PC and became an important part of the story, just because the PC in question proposed the idea. This is pretty much what declarations do on a regular basis. Well, maybe not on that scale, but still.
Lastly with a first game for a GM and new players what power level would be best to start the characters?
As UmbraLux says, 6 refresh (feet in the water) should be a good way to start. Players will be rather limited, though if they specialize can still be pretty powerful. You might want to try one of the introduction adventures. They have story and characters ready to go, with some of the character aspects, skills and powers still to be filled in by the players. I haven't played them yet, but it reads pretty solid and should at least get you into the system rather quickly. There are 3 case files currently available:
Neutral GroundsNight FearsEvil ActsNeutral grounds was the original beginners case file I think, though Night Fears should be just as good. I have not read Evil Acts yet, so I can't say much about it in that regard. I think if your group can agree on one of those for a first run, you will have the easiest way of getting into the system itself.
