Think like a kid for the intro. Here’s a few suggestions:
For the homemade gelatin - cut it into kid shapes.
If he/she won't eat eggs you could mix them, cook them flat & then cut them into more shapes.
Try apple cider or grape juice (1/2 juice, 1/2 water) frozen into popsicles.
The broiled beef patty can instead be rolled into little kid-size meatballs.

Unless symptoms are severe (cramping and diarrhea), one or two days on the intro diet are sufficient. If your child refuses to eat the intro diet foods, simply do the best you can to provide a very simple diet of easily digestible SCD™ legal foods. Get as close as you can to the intro diet with just a few basic foods you know your child can tolerate and will eat. After that, introduce new foods slowly. You may be able to return to a stricter intro diet later for a day or two to jump-start further progress. After doing the intro diet,cautiously introduce easy to digest foods and and carefully observe your child.