What is the best type of teaware? Earthenware, Stoneware, or Porcelain comparison

I really love the look of the unglazed porcelain.

I think what’s going on here is getting a little lost as you’ve focussed a lot of firing temp and haven’t talked about clay body: the difference is in the clay not the firing temperature. The firing temperature for each clay body is the temperature required to reach vitrification. If you overheat earthenware clay it will just entirely melt. So, the different firing temperature is as a result of the clay having different properties.

You are correct when you describe the properties of porcelain as being much tighter etc… but that is a property of the clay body and why it has a higher vitrification temp. The temp itself isn’t making it stronger.
You’re also correct that earthenware doesn’t fully vitrify.

being glazed or unglazed isn’t way to tell stoneware and earthenware pieces apart…

In fact I’d be surprised if your example of earthenware isn’t stoneware. My reasoning is that it has a crackle glaze and this is often seen in Raku glazed pieces (a Japanese glazing technique that makes use of an open flame) Raku is too hot for earthenware to survive - so that’s probably stoneware.

I love that first earthenware cup. I dig the cracked look.