A few questions..

[BirdOPrey5]

Problem 1:
Can't help you - never had this problem, do you have a custom style?

Problem 2:
There is no way I know of to delete posts of users simply by putting them into a usergroup. I use the "Delete as spam" function when deleting a spam message that gives me the option to delete all their other posts before banning them.

Problem 3:
Admin CP-> Vbulletin Options -> Message Posting and Editing Options -> The first option controls "Quick Reply" behavior. Choose "Yes, click not required"

Problem 4:
Not exactly sure what you mean, a thread prefix is just that, a user selctable prefix before a thread as a way to better organize thread topics. As part of the prefix you may use HTML codes to change the font style, color, etc.. to make the prefix stand out. I suppose you could also use an image tag to put a small graphic in it but I wouldn't think it would be useful to do anything more complicated then that.

Problem 5-

Please don't post using code boxes for standard text, it's very annoying. ;)