Red Admiral (Vanessa atalanta)
Monarch Butterfly (Danaus plexippus)
Variegated Meadowhawk (Sympetrum corruptum)
Unidentified fly (Let me know if you recognize it!)
ADDENDUM (12 February 2017): One of the suggestions I received about the fly in this post was that it could be a hover fly. I did a quick image search, and noticed a similar-looking hover fly here. I don't think it's the same species (based on the abdominal patterning), but it's very close, and I think it's likely the fly in the picture above is in the same family (Syrphidae).
Then I skimmed some information about syrphid flies, and learned that sometimes they eat aphids. In the field I had noticed that these flies were spending a lot of time around the tips of the Monterey Cypress. I wondered about what they were doing there (i.e., what was attracting them to those sites). Well, I went back and reviewed my photos and it looks like there might be tiny aphids on the cypress tips! Check it out — and note the arrow pointing to one of the possible aphids: