Is is possible to make mods for hairstyles (relatively) easily but changes to clothes is much more difficult, since every possible body position has to be individually accounted for, allowing the clothes to 'drape' realistically. Changes to the colour would be possible for most experienced modders, but not really styles.

The peeps only tell you to stop nagging if you praise them twice in succession for a particular action, then attempt to praise them again. If you still want to reward your peep use fruit or candy from the store instead.