1. Yes. The D50 mics are OK, but I think for what you are doing, the CA14>pre>m10 is much better.
2. if you have omnis, it's pretty easy.. .they are so nice and small, you can mount them on anything. Maybe use a chair placed in front of you, with the mics clipped as far apart as you can space them onto the back of the chair? Or you can use something simple like a ruler or other wooden object taped to the back of the chair to extend the distance between mics.
3. Yes, it should. Chris Church should be able to produce a pre that is appropriate for your needs if you let him know that in advance.