Now for the answers...
1. What game did Sonic become 16, and what game did he become 15 again?
Sonic the Hedgehog 2 is where he became 16. When he became 15 again is debateable between Sonic 3D Blast, and Sonic Adventure.
2. Who technically appeared first, Amy Rose and Metal Sonic, or Tails?
First, it was ment to be Metal Sonic and Amy Rose, since the game was meant to come out first, but for some reason, Sonic 2 beat it, so it was Tails.
3. What was the one and only Sonic game that the cartoon/Archie characters appeared in?
Sonic Spin Ball. Although I did forget about Mean Bean Machine, that game only featured Scratch from the cartoons, and the cartoon version of Eggman, Grounder, and Coconuts.
4. How old was Tails when he debuted, and what game did he jump 3 years ahead in?
He debuted at the age of 5. In Sonic Adventure, he turned 8.
5. Same question, but for Amy Rose this time.
She debuted at 8. In Sonic Adventure, she turned 12.
6. What purple character was the first Sonic character to use a gun? Whats his Japanese name, his US name, did he first debute in the comics or games, whats his occupation in the comics, and what is it in the games? Whats his species, both US and Japanese. And name the 3 games he appeared in, as well as the fourth game he was planned to be in, but never made it.
Japanese name, Fang. US name, Nack. Games, Sonic Triple Trouble. Weasel in the US, cross between a weasel and wolf in Japan. Sonic Triple Trouble (aka sonic and Tails 2), Sonic Drift 2, and Sonic the Fighters aka Sonic Champions. He was meant to be in Sonic Xtreame.
Bonus: What was Sonic originally going to be before he became a Hedgehog?
Hell if I know, thats why it was meant to be a bonus. Rabbit does seem familiar though.