Forge: get the 1.7.10 Recommended version
Pixelmon: Wait for the countdown and get Pixelmon 3.3.8
An easier step is to just download the server modpack at: http://www.technicpack.net/modpack/details/riks-pixelmon.362440
Welcome to Rikxelmon!
This! is one of those diamonds in the rough man seriously! Join now for some epic pokemon flashbacks to when we were younger and use to spend hours and hours playing this game. Rikxelmon strives to bring you this but with that minecraft feeling still looming around. We also offer a 0% lagg free environment from the time your on the server right to the time you log off. this is survival with some company along for the ride, There is no griefing or pvp is in a planned area so all your stuff will stay that way because we use one of the best plugins out there, grief prevention!