sounds like you have a solid plan and you should go with your gut. if you have the money, better gear for recording is always better in the long run for mixing. I used the AT4050 and sounded great and didn't have it hooked up to nothing special. just a normal mixer for my phantom power and the vocals came out just like i wanted them to sound.

I have a couple of 4047's, they're very smooth and detailed, a real gem.
As far as the mic pre is concerned, you might look at having a clean, transparent one like a Grace 101 for the mic you choose, and a more 'colored' one, like a GT The Brick for the instrument DI duties (or when you want some 'attitude' on the mic). Both of these will set you back about the same as the price of a Mini-Me. HOWEVER...
There have been several posts here like yours over the years; somebody has a bit of 'green' and wants to make a CD of their material on a Roland
(or Akai or Yammy) studio-in-your-lap. They keep throwing money at it-new mics, pre's, processors, etc. The problem is that these boxes have to cut corners to make it to the market, and to allow for enough tracks and recording time. The manufacturers are always developing data compression schemes to get the absolute max from the internal hard drives, and no matter what they claim, the audio quality suffers.
IMHO, you REALLY should look at a computer-based recording medium.
They have become so much better sounding and user friendly over the past couple of years, it's scarey.