RonYeah
-Credit Maker to buy enough furni to build a staircase

cookinator
-Speak catanese to persuade Mittens to come down

Armset
-Bird-Mode, transforming into an eagle and pluck Mittens out of the tree

Bunc.man
-Extra-Stretchiness to stretch up to where Mittens is stuck

@:Brody:@
-Parachute Materialization to be able manifest a parachute in sticky situation such as this one

HotGumbo
-Control of the elements (Earth, Wind, Fire) to use for platform-building and cloud-creating

H4th0r
-To be able to control all the Kitty Kibbles within a 10 mile radius to make a Kibbles staircase

Diluted-Flames
-Time-Shifting to go back in time and reverse events

DJPurity
-Ability fusion to infuse the tree with the power to grab Mittens with its branches and put it back down  

Humphrey.
-Ability to turn into any animal, a seductive cat in this case to lure Mittens down

Congrats! You are true Habbo Heroes:)