At idea 1. Sorry, but I don't like this idea, nor having an option too. Troll's could also take this a step too far, coming along and doing their business beside you.
At idea 2. There are thousands of extra creations, and putting them in will generally add a tonn of lag.
At idea 3. I like this idea, it'd make things a lot more orginixed.
At idea 4. A nice little idea, sometimes it does get tedious counting them all, but I rather enjoy it sometimes.
At idea 5. Another nice idea, only thing I'd worry about is the amount of paw-prints you'll be seeing around and then slowly fade. If you sit in Fluorite, you'll get a lot of extra lag due to the amount. Having an option to have it on or off would be good.
At idea 6. Not so sure about this idea, but it'd make RP more interesting.
At idea 7. I think just having a 'lick' option would be nice, but I'd scrap the request option. At idea 8. The nuzzle option from IT was very good, and I'm starting to miss it.
At idea 9. 'Rag Doll effect'? Do you mean like in a fight, a user can shake the other person like a rag-doll? This could be annoying, since power-players would really abuse this.
Some interesting ideas! +Floof. Also, could you not use that big text? Really makes things hard to see. :3