I will sheepishly display my lack of creativity in that yes, I have another song you can use for memory this week...and yes, it's a tune we already use. Eph. 6:14 can be loosely applied to the tune of "Found a Peanut"/"Clementine":
Stand firm, then
with the belt of
tru-uth BUCK-LED around your WAIST!
with the breastplate
If your child starts thinking this verse is full of prepositions, I do apologize.
As for the art project, it has so far been a success. Here's a picture of my son being outlined, then drawing and labeling the armor of God on his body shape. We looked at the online pictures of Roman armor first.