Thinking about how the characters’ appearances would differ in Pendulum of Destiny compared to canon.
Yusei obviously doesn’t have his prison marker, and he starts with the head mark instead of getting it later on. Aside from that, there’s no reason to think of him as looking any different from how he does in canon.
Jack looks the same, with the exception of a minor detail that I will explain under a cut (for spoilers’ sake). He might ride a different bike, though. (Reminder: duel runners and motorcycles are actually not the same thing!)
Akiza, Leo, Luna and Carly all look the same as they do in canon, again with the exception of a detail listed under the cut.
The Arc-V cast is where appearances really start to differ. Everyone there is a bit older compared to canon, so they would be taller and more mature-looking overall. A particular difference I had in mind is that Yuzu’s hair would be a bit longer, and outfit-wise, the princesses might wear something a bit fancier (since... well, they are princesses).
In this setting, dragons can shapeshift into a humanlike form, but by default, they still have horns and a tail in that form. They can also seal their power inside an artifact to take on a form that’s closer to that of a human, though there are still distinct differences - dragons in this “altered” form still have reptilian eyes (slit pupils) and slightly pointed ears, and their teeth are sharper than those of a human (distinct fangs). This distinction would apply to all four of the yu-boys, as they’re altered dragons here. Yuya in particular has heterochromic eyes - his left eye is green and his right eye is red, matching his true form as Odd-Eyes Pendulum Dragon.
Outfit-wise, there’s no reason to believe that their regular clothes would be that much different. Those clothes were magically generated upon their transformation to prevent the not-so-small issue of them being naked, and their clothes would suitably fit them. (Yuya might have his cape from the manga instead of the jacket he wears in the anime. Also, Yuto probably wouldn’t wear the red cloth on his arm.) Again, they’re a bit older, so their clothes would be upscaled appropriately, and they each have their draconic artifacts - Yuya has his pendulum necklace, Yuto has an ornate choker, Yugo wears a bracelet on his right wrist, and Yuri wears a single earring.
Shay is almost in his 20s here, so again, he would probably look older and more mature than he does in canon. The crest of the Raid Raptor takes the form of a large tattoo that spans a large portion of his back, centered near his shoulder blades, and it becomes visible through his clothing when he activates it (it lights up in a red glow). His outfit is... honestly a huge question mark in my mind. He’d probably wear the same clothes he does in canon, but he would have no need to wear the red cloth around his neck... but it’s such an iconic part of his design that it’s kinda hard to imagine him without it. lol
Cut for spoilers:
