The Stellar Journey of Bewilderment (Impossible Riddles)

You are traveling to see something. It's the only word that is over 5 letters long and has every other letter as "y". What is it?

At one point, you find a sign reading "Ali, Olivia, Wanda, and so on... only one will appear twice". What is the one that will appear twice?

You look past your shoulder to find a mysterious wizard. He approaches you to say that he goes by Valend. Valend shares a cryptic puzzle:

The wizard Valend then reveals he had just come from the year 1000. He shares the following:

The mention of the year 1000 brings up a question that's been haunting you. What is 1000 in bijective hexavigesimal using no numerals?

Valend shares a final message. "I'll let you in on a secret. Valend's actually a short name. You can lengthen it a few ways by adding specific letters between." He pauses. "Take the V and A, for instance. You could make it VIA or VBA. And right now, YOU are taking a QSUIBNCCDZ. Convenient how YOU doesn't need any letters between the letters, huh?"

As he leaves, you spy some text on the back of his shirt. It says something like, "I'm so cool that there is a municipality whose name contains mine—but they spelled my name wrong." What is this referring to?

In front of you lays a short teetering bridge. In its heyday, it likely had as many as 14 stepping points, but now only 5 or 6 remain (both are equally likely).

You are nearing your destination when you stumble across 31 trees. Each are labelled, although it is hard to make out anything. One reads "Sat...", one seems to be a three-digit number, and all but eight are only one word long. A handful are countries. Only one of them is three words long. What does it say?

As you have nearly reached your destination, you find a sign reading: 1 53
_(HI) There is another beside it. 90 A 7 19 39 8 92, 67 15 63 1 AD 9 92 7
What does it say?