So I just bought an Ibanez SG style body and noticed that there aren't too many new RG Wizard II or Wizard III necks floating around on the internet for sale, However I noticed that there's a CRAP TON of tele necks and strat necks. I was wondering if I could fit one of those bad boys on my SG? I heard that the only thing that matters is scale length, which an Ibanez SG should be 25.5" am I right?
No. Scale length is important but the neck pocket dimensions and to a lesser extent the screw holes are also critical. You'll need to find the specs for your body's neck pocket and see if they match the neck you want to get. You can probably find one that does fit, especially if you're lucky and it's a standard Fender or Squier size pocket, but you can't just buy a 25.5" neck and know it will work.