Those MSR mugs you have are the 10 oz ones right? I'd think they'd be a little small but doable. I'd rather have their 12 oz ones, but what's a couple more ounces of coffee?
Like you, I don't need a bigger pot (2.5 lit) as our 1.75 lit pot seems to be more than adequate. But I also see that if I went with the MSR Alpinist 2 System set I could add that third cup. Though it's more than what we need it's overall size is smaller as the cups are now stashed away.And at 23 oz it weighs less than my 34 oz system I have now.
But that brings me back around to whether or not I could get three mugs into my current pot. The sizes aren't so different when the lack of bowls are considered. And my skillet lid only rests on top. The bag is what holds it together.
I am slightly concerned about the lids not attaching securely. A lid is a good thing on a little one's mug! And might be good for us on really cold days.
"Were I to leave where else would I go? Your words of life and of truth You hold." - Third Day