1. i'm pretty sure that unohana chose someone from her squad to clean her cell, i dont think central 46 pick stupid things like that.

2. he helped them only to help rukia, i dont remember him fighting anyone so he didnt exactly betray soul society.
by the time ichigo beat renji, it proved that grunts wouldnt take more than a second of his time, hanatarou also couldnt know the location of every single grunt, what if one happened to be walking around by the tower where rukia was kept? (granted this time it was zaraki...)
knockout pill...right, umm you think ichigo who by this point also took out zaraki already, couldnt beat a few more grunts?

3. ...acctually i dont see whats so hard to "buy" unless you saying he knew where ichigo and ganju was, and if thats your case, aizen had no way of seeing which of them was strongest at that time, if he were to send hanatarou to get them, how would he know which one to send to? aizen also knew yoruichi was there, so technically the smartest thing to do would've been to tag along yoruichi, but then again, how do you tag on with a cat? wait i'm just ranting here...

4. lets see, it was either help them, and save the girl he was already friends with...or stick around getting left alone, wandering around soul soceity some more and running into more 11th division people to beat on him...i'm pretty sure i would've chose the first one.

5. aizen described where he was going as above the heavens...what makes you think he cant see everything already? of course, he might not be able to, but thats as much of a inference as you saying hanatarou is a spy. i dont think aizen would leave behind a weak spy...and also, i'm pretty sure all who were paired up with aizen wanted more power too, by staying in soul society, that person would be excluded...so why would anyone do it??

6. sure a healer would be a great asset, but then why would aizen go for hanatarou? besides if people from 4th division can use their reiatsu for healing, why cant aizen?

i dont have anything against you, i was just pointing out how some of your points in this theory are invalid.