Yes, as long as you don't actually add a full profile for your creations on your wall. If you want to make a fan character you must make a page called "FanChar:*Your Username*:*Character name*" (see Rules of Fanon for more information).
Also if you want to ask a question post on mine or another Admins wall (see here for a list of Admins) as we do not get notified if you post on your own Message Wall :)
Whenever you edit a canon page please always put an edit summary no matter how small the edit is! (See Editing rules and common mistakes). Also, if you are making a change to a characters Voice Actor or anything similar please link to proof. Thank you!