Tell the Vorlons when he went back in time and became Valen? Did he need to TELL them things, if they could read his mind?

How much did they even want to know; did he meet Kosh back then, and if so did he tell Kosh what would happen to him when he first went to B5? In the original pilot "The Gathering," Kosh seemed a bit surprised to meet him. I think later versions cut out his greeting "Valen."

Which I suppose means that maybe Sinclair at least didn't tell him that it was/would be an imposter.

etc, etc.