Can all 1/6 dolls wear the same shoes?

You should be able to find measurements of the inner sole on the shoe's product page most of the time. Compare them to the measurements of your doll's foot from the maker. If you can't find the measurements, try to reach out to the seller for them!
Sometimes the shoe is made for a narrower or wider foot than your doll within the same scale. And although most makers try to keep the feet in a similar size as existing dolls in that scale, it's a huge bummer to get your adorable doll shoes home, only to find that you can't shove your doll's feet into them

 

If the shoe ends up being too loose on the sides you can add a little thickness with socks. And a close-toed shoe that is a little too long can be padded in the toe. Just make sure you don't go too small

 

You definitely should look carefully at the measurements, as 1:6 is not used properly within this genre of dolls, and most other dolls in general. The term literally means a real life object that many times smaller than the real life one. 1:6 scale means six times smaller than the actual object in this case a humanoid doll, would be proportioned like an actual human to be 1:6, if it's not proportioned like a human six times smaller it's not 1:6. Barbie for example is not considered 1:6 to most actual 1:6 collectors, because her head is too big, her feet and hands are too small compared to human proportions. A lot of BJD sellers call chubby baby 30cm-ish dolls 1:6, but that would mean giant 6-foot tall babies IRL, but also that means a shoe that won't fit mature dolls that are 30cm, because the proportions are not similar. Because these dolls are not actually in scale, most shoes that are labeled as 1:6 wont fit all, because more likely than not, none of them are actually for 1:6 scale dolls. I hope that helps and doesn't confuse you. Just look for the foot measurements of your doll and compare them to the ones you're looking to purchase. Also, watch out for 1:6 action figure shoes, those are actually scaled and fit most action figures but not all of them are meant to be worn on feet, and have sculpted or filled in spaces that are meant to go on round joints for action figures, you won't be able to use them on any BJD unless you're willing to modify the shoes. Good luck! (:

 

You can also look at yo sd shoes as will. I saw a picture of a tinyfox 1/6 wearing the rainbow high boy doll shoes. l will see if l can find a picture for you.

 

Anything from a BJD site labeled "1/6" usually means YoSD sized, and should fit your new doll! BJD sites rarely sell anything intended for an actual 1/6 scale like Enzyme is describing, but it has come to be a way of referring to the child-like dolls in the 26cm (ish) range.