Okay so let me point a few things out. A. That axle as long as it's straight won't need to be replaced. B. The rotor looks fine just rusty, maybe some new pads and put new fluid in the system.
You need to research where you are going to race and see what classes they offer. Yes the lo206 is expensive but guys are getting 5+ years out of a bottom end. Refresh the head at the end of the season and it's good for the next. Majority of people on this forum are into dirt oval and I am one of them so I won't talk about values because I just don't deal with sprint stuff.
From what I've heard, CRG is a stiffer chassis to handle higher horsepower applications but people make them work with a 206.
Obviously you're younger and not going to be footing the bill for this stuff so you and whoever is buying it need to do as much research as possible before buying anything. Nothing against the kid who told you the axle and brakes need replaced but don't listen to him. I'd look for the most complete setup I could find that fits whatever class it is I want to run in. It saves a bunch of headaches having to piece together the puzzle. Go to wherever your planning on racing and go socialize, there is no better way to get information than talking to the people who run where you are planning on going. There may even be a better opportunity to buy a complete setup or people there may know of something that isn't listed for sale online and can help you.
Welcome to the forum and I wish you the best in your endeavor.