Other mistake: At the prison, Bill meets Alicia, the same woman who gave Leanne a ride to the Hill house in Season Two ("Leanne's Saga"). Same voice, tattoo on the arm, and general appearance. Alicia tells him that she was in prison for killing her boyfriend. So it's odd that she was free in Season Two. Most likely, a sentence for homicide or manslaughter would be at least five years, and that much time has not passed. Otherwise, Bobby, Connie, and Joseph would be in their late teens.
Other mistake: The premise of this episode makes no sense. Bobby and Connie have previously spent a lot of time together and/or with Joseph. They were also shown on "dates", i.e. the high school dance where No Doubt played. Basically, they were a steady junior high/middle school couple. However, in this episode, they are suddenly "too different" and can barely get through a few dates together.
Answer: Jeffrey Boomhauer is a Texas Ranger as can be seen in the final episode at the end when he sets his wallet down, it flips open revealing a Texas Ranger badge.