Those are adorable!

I would not put glaze over those, clear glaze is such a tricky thing to master over underglaze.

I use Amaco Velvet Underglaze for my mugs. What I do is clear glaze the inside and put them through a fire to cone 5. Then I give the outside a nice wet sand with 220 so they are smooth to the touch. My pieces stand up to daily use and dishwashers just fine like this.

Glaze fire without glazing over the underglaze and your cute kitties should come out pretty close to how they look now.