How do I find out whether a specific course is CEU-eligible?

Look for the CEU information on the course page itself rather than inferring it from the family, hour count or title. Where an offering carries CEU credit, the page states it.

If you are enrolling specifically to satisfy a requirement, take one further step before purchasing: confirm with your licensing board, employer or certifying organization that a course of that type and subject will be accepted.

Verifying first is far easier than discovering afterwards that education you completed does not count.