I'm honestly hoping it ends up being Apollo Justice 2, but I'd be fine with a Phoenix Wright 4. (I'd be rather displeased if they retcon AJ out instead of just having PW4 take place afterwards, though.)
That is in fact the reason. Apparently the original plan was for AJ to have an entirely new cast, but the higher-ups were all "No, put Phoenix in the game so it'll sell more!" And thus Hobonix was created.
Fair enough, but you should really try getting hold of one of the games, I know it's tricky to get the ds ones as they are old games so I would try and grab them if you have money even if you play it in a messed up order. I would look into the iOS version too if you have an iPod touch/iPhone/iPad.