@keith @seanhoots Thanks for all that – I’m no longer wrapped around the axle. 
What I heard was: For dates that people don’t associate with a time zone (like a birthdate,) save them as UTC, search for them in UTC, and format them UTC. In doing so, you can just use a single date field.
More testing to be had, but this seems fine:
Load the scripts in html element
Entering the birthdate:
Convert DOB to UTC before adding to database
Then for the search:
Convert search date to UTC
Reference the UTC search date in the search and set the time ranges
For testing, this was helpful:
Thanks again Gents!