The answer to number 2 is easy, AutoDesk Fusion 360. It's free to startups and hobbyists. Full professional CAD/CAM software.
I would start here https://academy.titansofcnc.com/
The answer to numbers 1 and 3 are much more difficult. It depends on your budget and what parts you want to make. For a new machine you could spend from about $7000 to well over $1,000,000. I would think as a minimum you would need both a lathe and a milling machine. For one-off parts, many times, I use a combination of manual and CNC equipment.