How do I give a recommendation of excellence to a Pluto character?

I think you can contact the park and they can get your message to the appropriate personnel based on the time/date of your visit

Tweet about it. Be sure to include @WDWToday in your tweet. That is the official Disney account. When you Tweet to @WDWToday, use the hashtag cast compliment - #castcompliment. Disney monitors that account. They look for those kind of things.  They see those cast compliments and actually Tweet back to you and say thank you and something like that. When you do that cast compliment to @WDWToday, Disney takes that and they put it in the Cast Member's files. It is a good way of thanking a Cast Member. It really does get attention. If you had a picture it really helps. From: https://www.dadsguidetowdw.com/how-to-thank-a-cast-member-at-walt-disney-world.html