So is this all ok?

Stan

Usually yes. Keep in mind, your FILED alternate does not have to be the
actual field you divert to. You simply have to have "ON PAPER" a field
that is within your capabilities (fuel) and specified weather conditions.

There may be DOZENS of other fields nearby/in range that are safe and
useable, but are unable to be listed as legal alternates.

I say usually. A big part of this decision is what the weather is across
the region. Is the entire region socked in low/hard or is there a
localized weather phenom that will move on/clear up/etc?

From a legal standpoint, its good to go. From a safety standpoint, its
all relative. If it doesnt worsen, its just as safe as any other IFR
flight to near minimums. If the whole region is blanketed by low clouds
you may shut yourself out.

With regards to your example (assuming ILS our at Carlsbad), as a
general rule, I would want to have an alternate that had a working ILS
with good precision minimums available to me, so that there is a large
margin between the higher "alternate" minimums and the actual minimums
that I will fly the approach to.

Dave