Character names seem to place this film around 1992

Great observation. Maybe the script was written that long ago and has been waiting this long to be developed. The movie certainly struck me as being very old fashioned in the sense that it was melodramatic and cliched and the humor was cheesy. It did seem like a very 1990's-era TV movie now that you mention it.

Henry was named for one of his father's law profs... therefore the time period of the name is not relevant. If he was named for someone his father respected, then it is likely that Glen and Dale were also... especially Glen may have been named for one of his Dad or Mom's brothers ro fathers. My son was born in the late 90s and has had several Erics in his classes, Scout Troops, etc. Likewise, my daughter was born at the turn of this century and both she and her brother have known several Joes. All three female names will be found in my daughter's classes. Small town families, especially religious ones choose family names (and Catholics tend toward Saint's names... as other denominations may well, if not Biblical names). Your theory is very flawed.

Or, spoiler alert, they are from Indiana and not California so there would be a lot less Madison, Baxter, Spencer, Keegan, or Jamarcus