Based off of Caydes vanguard dare technically Prince Uldren is the new Hunter Vanguard

Pfft, the Hunters went more than 2 years without a Vanguard when Kauko disappeared. The Hunters’ll be [i]fiiiiine.[/i]

This has been addressed by the hunter populace. Most have fled the tower to avoid the nomination and conversation of the subject. Hunters don't really like being stationary in the Tower.

Shiro-4 is the best option.

Hunters are notorious for being lone wolves and avoiding responsibility. A Hunter Vanguard is chosen through the Vanguard Dare, which is given by the current Vanguard to a possible successor. So if the successor loses the Dare, they become the next Vanguard. However, in the case of Cayde’s Vanguard Dare, a Hunter had to kill him. Problem here is that Uldren wasn’t a Hunter, let alone a Guardian when he killed Cayde, thus rendering the Dare obsolete. So in the event a Vanguard Dare has failed, the remaining Vangaurd have to gather Hunters and come up with a Dare on their own. This is why canonically, nearly every Hunter in the City is avoiding the Tower and Vanguard. That’s why in the Lore Tab of Tommy’s Matchbook, Ghost (the Hunter) is hiding out in an abandoned building and bribing Aunor (a Warlock with Vanguard connections) to keep his location a secret, as he doesn’t want to be stuck with the duties and responsibility of a Vanguard.

Yes. Hunter Vanguards are different in the way they’re chosen compared to the Warlock and Titan ones. The Hunter that succeeds the last, is meant to have lost a dare. For example Kuko Swiftriver was declared dead, so Andal Brask And Cayde-6 decided to hunt down Taniks, the Scarred; loser would become vanguard. Cayde “won” and so Andal joined the brass. Cayde left a dare. If a hunter kills him, they take his place. However this dare is very questionable; and some have argued not to take it seriously. However, if you took the dare seriously, it was never fulfilled. Uldren Sov, a non guardian killed Cayde. So technically he has no successor. Now I know that Uldren has since been revived as a Lightbarer. But he is looked down on by everyone. He also can’t be vanguard because of the [b]Instability[/b] lore tab from [i]Stolen Intelligence[/i]. I’ll let you read the book on your own, but it basically says that the Vanguard traced Cayde’s death back to the true culprit, they’d have to ‘elect a hive god to our council’. They also have questioned Cayde’s dare because of it’s contents and because it went unfulfilled. So they have left the vacancy to be filled by a well qualified and capable hunter, which will be chosen in the form of debate. But all Hunters have left the Tower and are in Hiding. Tommy’s Matchbox introduces Tommy the Ghost, and Ghost the Hunter. They basically bribe Aunor with gun’s components as to leave them be and not rat out their location. So we know that Aunor, a warlock of the Praxic Order; has been searching for the Hunters; and it’s likely that since we had this one, we’ll learn of more.