Forgot to mention for the previous volume that another reason I wanted to re-read Yuu Yuu Hakusho was in preparation for getting back into Bleach, because of similarities between being a Spirit Detective and a Substitute Shinigami....
I guess, in the seven-plus years since I've last read this volume, I'd forgotten that its contents aren't as good as Volume 1's. But I'll still give it a perfect score because it's my Goodreads account and I can do what I want!
There's still no real, definitive hints toward Yusuke becoming a Spirit Detective, though at least the last chapter has Koenma mention something about Yusuke's real test starting now that he's come back to life. This is something I like to think about with Jump manga from a certain era (basically, Kinnikuman to Bleach, I guess?): the magazine allowed more freedom for mangaka to do their own thing for a couple dozen chapters before deciding for sure that they want to focus on battles. That is, Kinnikuman is an Ultraman parody for a good while before becoming the choujin wrestling manga we know and love. Dragon Ball is an adventure comedy where Son Goku defeats most of his foes with minimal effort before the first Tenkaichi Budokai. Shaman King, which will start some years after Yuu Yuu Hakusho, will follow similar footsteps with episodic exorcisms before the Shaman Fight is first mentioned. Bleach, later still, will have monster-of-the-week Hollow battles before we get more "human" antagonists with the arrival of Byakuya and Renji. Today, new Jump mangaka cannot dick around; they must establish their main story as soon as possible, lest they get cancelled in under three volumes. It's actually quite interesting to see how leisurely Togashi is with YYH here, versus his later Hunter x Hunter which begins almost immediately with the protagonist Gon seeking his Hunter's License; Yusuke has no idea what a Spirit Detective is right now, nor does he have any reason to know!
Togashi-sensei lays some more groundwork for the eventual shift to a battle focus, in the least likely manner imaginable: the first time we see weaponized reiki is from the little girl ghost in Chapter 10, whose attack against Yusuke will form the basis of his later Reigun technique.
The bunnysuit girl who does the recap at the beginning of Chapter 16 shows Togashi can really draw cute girls (though I guess she kind of just has the same face as Botan...?), so it's funny that YYH and especially HxH will end up as such sausage-fests.