Dennis Quaid's twins are extras in the diner scene. His daughter is the one that points towards Quaid's character during his health incident.
Dennis Quaid's character was a quarterback in high school. He also played a quarterback in Any Given Sunday (1999). If you notice the picture Bart has of his dad, it's a picture of Quaid in his #19 black jersey from Any Given Sunday.
The release date of I Can Only Imagine was 3/16. John 3:16 is one of the most widely quoted verses from the Bible, and has been called the most famous Bible verse.
During the opening scene set in 1985, young Bart is riding his bike through town. He passes a movie theater showing the titles of Jaws 3-D (1983) and The Goonies (1985) on the marquee. Dennis Quaid, who plays Bart's father Arthur, played the lead role of Mike Brody in Jaws 3-D in 1983.