Thank you very much! I still don't have a full set of data for knowing certain things, but after today's run, I can say without a doubt that Serebii's Dream Point/action chart is definitely wrong.
Things I can confirm so far:
* Watering a neighbor's berries DOES award 10 Dream Points per berry watered.
* Watering your own berries DOES NOT award any Dream Points. So do your Dream Pals a favor and leave your berries unwatered unless they REALLY need it, so they can actually get Dream Points out of it!
* Harvesting berries DOES NOT award ANY Dream Points whatsoever, so unfortunately a full crop of Oran Berries isn't going to let you unlock more areas or Pokémon any faster.
* Succeeding at any mini-game awards 20 Dream Points. It's not based on how well or how poorly you score, and different games don't award different amounts of Dream Points. It is always 20.
* Conversely, failing at any mini-game does not give you any Dream Points as a consolation; you DO NOT earn ANY Dream Points from failing.
* If you have earned 0-90 Dream Points in your current session, your Pokémon will have an ellipsis as its mouseover icon. If you have earned 100-190 Dream Points in your current session, your Pokémon will have a ^_^ emoticon as its mouseover icon. If you have earned 200 Dream Points or greater in your current session, your Pokémon will have a music note as its mouseover icon. Though I'm still testing this, I believe the music note will stay the Pokémon's mouseover icon until you reach 500 Dream Points earned in your current session. I believe it is at this point that the mouseover icon becomes a heart, and is therefore indicative that the Pokémon will gain a level upon being woken up (since 500 Dream Points in a single session will cause a Pokémon to level up).