After the Green Ranger breaks in to the Command Center, Zordon says that only someone who has a Power Coin can get in. However, Zordon does not give the Rangers the Power Crystals until they fight King Sphinx, and, since the Coins are seen transforming from the Crystals, it doesn't make sense that one would be introduced before the other. So, the Rangers should not have been able to get into the Command Center before that.
When Rita brainwashes Tommy and turns him into the green ranger, they show the silhouette of the Japanese actor and not Tommy.