Hiei: Get him to stand next to my little brother, then tease him about being the same height as a nine-year-old. I might also get him to teach me swordsmanship.
Yusuke: Hit him and order him to take kaeko on a proper date.
Kaeko: Talk about boys, art, maybe try to figure out why she's put up with Yusuke all these years.
Kuwabara: "Can I see Iekichi?" Then give him pointers on how to get further with Yukina.
Yukina: Try to determine her true age. (My sister's think she's the demon equivelent of ten. Which would make her way underage for Kuwabara.

Koenma: Ask him why he looks like a toddler most of the time.
Botan: Talk about boys, hang out, try to determine if she has feelings for Kurama then dare her to ask him out. And make sure she gives me details afterwards.
This would be so cool!