1. I would think it would be fine.
2. You won't get amazing earth shaking effects without a sub in that configuration. Whether or not you can live with that for a while, is entirely up to you. I did so with a pair of Infiniti's for years, but they also had 12" woofers.
3. Probably not, but you'd have to talk to Amie.
Personally, If I were to do a gradual purchase, I'd go the following route. Combine steps as money allows.
Step 1: Buy fronts.
Step 2: Buy Sub
Step 3: Buy Center
Step 4: Buy surrounds
Step 5: Buy rear
And I'd devote as much money as I could to each step. But that's just me.
