Karasu not seems 10 feet tall (10 feet is 3,05 meters). I think the real heights would be:
TEAM URAMESHI
Yusuke = 5' 8
Kuwabara = 6' 3
Kurama = 5' 11 (Shuichi's form) / 7' 0 (Yoko form)
Hiei = 4' 10
Koenma = 6' 1 (Adult form)
TEAM TOGURO
Younger Toguro = between 7' 10 and 8' 0 (Base form)
Elder Toguro = 4' 0
Bui = 6' 8 (He's not 9 feet, compared with Sakyo and Younger Toguro)
Karasu = 7' 2 (About the height of Yoko Kurama)
Sakyo = 6' 1 (He's is a normal human, and about Adult Koenma's height)
THIS IS NO OFFICIAL DATA, ONLY MY THEORY.
I know that Juri says Bui's height is 9 feet (Episode Hiei VS Bui), and listed this in ABSOLUTEANIME.COM, but:
1) If i'm not wrong, this is only in English dub of the anime (not in manga, and no in other dubs).
2) If Bui is 9 feet tall, Sakyo is, at least, 8' 5. And Sakyo is about the height of Adult Koenma.
3) Karasu's height was estimated with Bui's height, and if Bui's height is wrong, obviously, Karasu's height too.
EDITS:
I think Sakyo is atleast 5-6 inches taller than adult Koenma. If you watch the episode where Koenma talks with Sakyo, they pan out and you can see them both in full view. The top of Koenma's head comes up to Sakyo's mouth. Since we know Koenma is around Kuwabara's height (who's 6'3), we can say Koenma is around 6'1 to 6'2, putting Sakyo in the 6'7 to 6'8 range.
Also when Younger Toguro shows off his power, there's a scene where he goes behind Yusuke and Yusuke only comes up a little past Toguro's elbow. Since Yusuke's is around 5'8", this would probably put Toguro in the mid 7 foot range, probably 7'8 to 7'9.