[Rhod the Red]

"3a. Gandalf calls himself a steward."

In one instance he refered to himself as one. This once, not other times. Other times as wizard. Usually from a third-person perspective though, when talking about 'wizards' and 'The Wise'.

"where and whenever he wished." In the sense that there was no limit? We have no knowledge if there is or isn't a limit. That's conjecture to assert perhaps Denethor somehow saw across the Western seas to Valinor and watched the Istari talk about taking on their role in Middle-earth.