I coached a lot of youth football. A couple of points and questions, although admittedly I never coached 5 on 5 - just 7 on 7 and 11-man tackle.
Are coaches allowed in the huddle? If so, draws your plays on paper and have them laminated. Show the plays as you call the name of the play. Also, you play like you practice, so follow the same routine in practice.
Five plays is not too many plays, in fact it is too few. I tried to have the players memorize the same number of plays as their age; and that is the same play to the right or left. So, you should be targeting 7-9 plays, which can be run left or right. For tackle it was generally dive, off-tackle, sweep, counter, reverse, play action pass, quick pass, roll out pass (all out of shotgun). Would also add one to three I plays later in the season.
Also, think about overloading one side. That is always a killer in youth football. If D doesn't match, you have numbers strong side; if D does match run your stud weak side where he will have more field to operate. Something like this (to both Right or Left):
C Slot WR
QB RB
Can run QB off-tackle, QB sweep, counter to RB, reverse to WR, roll out pass to Slot on an out with WR picking or running deep, pass to WR on a fly. if the D does match the overload, have QB run to weak side and use athleticism