I think you hit the nail on the head at the end - work with what you have at the moment and see what you come up with. You have to start someplace, right? There's nothing as frightening as a blank page or a blank canvas - getting something on there to start with is half the battle.

I was throwing this stuff our for starting out. As you write more songs, you may choose to take your audience into more consideration to make something that is more "commercial". Some would say that is selling out and you aren't being true to yourself. Personally, I think if you write stuff that resonates with you at some level, your audience will pick up on that and like it for what it is reguardless of what category it fits in.

Chris Schlagel is "da man" with figuring out what key a set of chords go to. Theory isn't my strong point, so I can't figure out off the top of my head what scale(s) would be suitable over that chord sequence. The F5 may give you some choices and whichever you chose could give it a minor or major feel.