In the last pic they look fine to me. It looks like its just the oldest fronds are dying off naturally. Are the fronds/leaves pictured above the oldest ones at the bottom? And do you know for sure if they are CA fan palms?

I don't think you have anything to worry about if those are just the oldest fronds. Brown spots could mean fungal disease though. And if they are pure CA fan palms you'll have to keep an eye on them. They don't really like humid summers and easily die from fungal complications.Even over here in the West where humidity is very low they don't really do so well on the coast where humidity is higher.
I've had brown spots (fungal disease) kill 2 of my coco's before. But if it were a fungal problem you'd see brown spots on healthy fronds too.

- US_Marine

Thanks very much for your reply. Yes, these are the older fronds at the bottom which have the yellowing/black spots. Although, the larger and newer ones at the top also have small yellow and black spots; except they're very small. If they get any larger, should I assume its fungal disease? What action would I have to take next?

I don't know 100% if they're California fan palms, although the guy I bought them from said he started growing them in December- then we hit a hot spell, and they started sprouting by late December. I just bought these around mid-May and they've been growing pretty fast. He said they were California fan palms.

Very interesting about the humidity. Didn't know that, although it makes sense now since I know California isn't humid like it is here. Any way I can reduce the humidity? Maybe not mist the leaves as much or at all?

Humid here too now. Us Marine right about those black spots, a few years back I ordered a Canary Island Date from Miiami, Fl.. I almost sent it back--covered in black spot. Figured it was the humidity and kept it. Today, it is fine having long grown out of its issues w. Florida humidity.