I'm sorry, but Grinite and Batuella are right. Let me list the problems, and why they are problems:
1) He cannot, and I repeat, cannot know canon moves, unless he has actually learned them from the actual characters (as in, from those who have rped them, not npc)
2) Goku killed the guy by accident? Okay... I find that very hard to believe. I mean sure Goku is powerful and all, but his first post was only a few months ago (add in a few extra fictional months) so by the time this Joseph and Goku had battled (being a year prior), Goku would've been the exact same strength, making it impossible for him to kill Joseph without killing himself. And so far, I don't think our Goku has died yet, though I may be wrong in that account.
3) Why in the heck would Raditz be willing to teach anyone? I mean c'mon, I know this is an AU roleplay, but the character personalities are mostly the same. And Raditz was an utter ass, he wouldn't teach someone. That and how did he get to Hell when he hasn't died either? (again correct me if I'm wrong guys)
4) King Vegeta had a power level of (sorry for invoking the meme) of over 9000!!!! And though someone is gonna need a big explanation as to where all that power went should someone decide to rp as him, the point of the matter is, Joseph wouldn't be even close to being strong enough to beat him.#
As for the space pod, I personally see no trouble with it as long as you kindly remember that you will not have said space pod should you start rping.