I could add... I've often done something like this, but I use the tops of flat lids. I smear whatever on the lid, and the they lick off to eat. I guess they enjoy it. It makes it last longer, that's for sure.
I use a vegan sugar free yogurt, hummus, peanut butter mixed with oil so it's not too sticky, and whatever else I think they'll like. I think I did avocado once.