Chocolate cereal muffins

I was cleaning my pantry, and I found a couple of bags of stale cereals. It was a great way to use them, it turned out very delicious.

I used Cheerios and two large over ripe bananas instead of yogurt and they turned out great. This is really a use what you have recipe.

These were very "use what you have" for me. We had golden graham cereal that my kids never finished, so I made a non-chocolate version. Didn't have yogurt, so doubled the oil. My batter was way too thick, so I thinned with splashes of milk to get to the right consistency.

Any suggestions on what to replace the yogurt with? Would milk be fine?