First of all, welcome to the club Dante. You didn't have to enclose your msn though. It's alright. Anyways, i'll add you.
Xeim, on Adult Swin, they're on which episode? So as to know when to use spoilers next time...
About the subject with Urahara, Yoruichi & Kurosaki.
Spoiler: In episode 111, Kurosaki Isshin fights against the Grand Fisher in his immature Arrancar form & kills it. Then he makes it clear that he was a Shinigami Captain as well, both by his clothing & by mentioning that Captains can measure the size of their Zanpakutou. So, it's clear why he would have a close relationship with Kisuke & Shihouin, who were Captains as well.
When it comes to their being controlled by Soul Society after exiling them, Andromeda said that there would be a risk of losing Captains while trying to fight them. Since they all were captains, i think that by sending the rest 10 Captains againast them, that would be the way for Soul Society to restrict their powers & their movements. Even Yamamoto could do that alone.
I have some questions.
1) Is there a mention about the Division in which Isshin was Captain? (probably not yet...)
2) Kisuke & Shihouin are using gigai as well? Beacuse if so, Kisuke wouldn't be able to use his blade, Benihime. ( again probably not )
Furthermore, it seems that Souls inside gigais can mate with humans. Otherwise, Ichigo is not Isshin's son. (....no comment on this one...)
About your character equilavents, i agree with Jaken & Yachiru...but i think that the little girl, Rin (i think) , who travels with Sesshomaru is more like Yachiru. Not just because they both are girls & the cute-adoralbe type, but, come to think of it, Jaken seems sometimes intimidated by Sesshomaru, while Rin never seems to be afraid of him, from the episodes i've watched that is.