New Machine Build compilation of parts

I've decided to build a CNC ... my plan is to start putting common parts together and continue to research as I go along.

I've already purchased

1. 8mm (608) Roller skate wheels for the linear slide;
2. 8mm x 10mm Spacers;
3. Emergency Stop Switch and
4. 8 wire 1.8 4 ANGLE stepper motor

I am going to use single driver boards so if one blows it can be easily replaced. Ebay has a Stepper Motor+ Driver Board ULN2003 5V 4-phase 5 line. These drivers are cheap, but I don't know if they are the right ones. I liked the idea of getting the extra stepper motors to be repurposed elsewhere.

I'm looking at pin connectors, but don't know if I will need 4 or 8 pins - haven't gotten that far yet.

I am going to use MDF, but now I'm thinking of using the 8020 aluminum for the slide rails and MDF for the frame. Will the skate bearing fit in the aluminum channel and move freely?

I also want to use pulleys and timing belts, but haven't decided on all the sizes yet.

This is going to be a slow go, so I hope y'all will bear with me because I need all the help I can get. I don't have months to research because this is a necessity- I always think it's wise to put my money into something I can build upon than merely purchase something, i.e., it's better to buy tools that I can reuse than to pay somebody to do it for me.

I don't have a name for my build yet, but thought "MOCK I" might be appropriate. :)