There's 649 Pokemon in the dex.
Uhm, I'm not quite sure what I'm supposed to do in this thread. The instructions aren't too clear... Do we make our own Pokemon up, and give it a name? I'm going to go with that.
I'd clearly have a guitar Pokemon, and give them names that are as ridiculous as they are. Perhaps for the first evo "Fretting", then "Playing", and finally "Shredding". Yeah, beat that for a lack of creativity. That would fit right at home in the 4th gen.
Yes, you can, its very easy! (For example Propeltot, Flutter, and Skylar the Normal/Flying type of Sinjhoenntova Region) Make your own pokemon if you have a pic, name it, and then give it a type. Also give your pokemon a moveset to show off, and give it a pokedex description to tell people about it. (For Example, Flutter: Twin Tail Pokemon, Because of its two tails, Flutter can also carry people across Sinjhoenntova without tiring out.)