The Pendant+Telepod opens gates that are there. In the original timeline, Marle still went on the telepod, nothing indicates otherwise, and she did not get sent back in time. Thats really the only time you need the pendant for gates. The gatekey works alone, not requiring the pendant, and you would be crazy to say that the gatekey creates gates. Same thing with the pendant.
The entity created gates.
I gave partial role, because although the entity only influenced a few things, they were big things. I couldn't bring myself to imply that it hardly did anything.