Welcome to Smogon! Take a moment to read the Introduction to Smogon for a run-down on everything Smogon, and make sure you take some time to read the global rules.
Yes, you can use any Pokemon or item that's not banned in Ubers for your "god" slot -- it doesn't have to be exclusive to Ubers. If you have any more questions I tried to answer any potential confusions in the Q&A section of my thread.
If you go with my suggestion, can god Latios/Latias hold the Soul Dew?