The letters, from top center going clockwise are Z, R, P, T, S, K, J, R, and Z.
I didn’t pay attention for the longest time, that there are Hylian letters around these Yiga footsoldiers when they do this thing right before disappearing! According to the Zelda wiki, they stand for:
Zen (Absolute)
Rin (Power)
Pyō (Energy)
Tō (Harmony)
Sha (Healing)
Kai (Intuition)
Jin (Awareness)
Retsu (Dimension)
Zai (Creation)
Also according to Zelda wiki, these are Kuji-in, or Nine Hand Seals.
The text above the Triforce mark reads “Hyrule Kingdom” and the text below says “Power, Wisdom, Courage”. I did not discover this on my own, but I found out about it in this reddit post. I think this is really a neat one!
Also on the Zelda wiki I noticed this addition from Creating a Champion (page 135). The letters say “Sunaza” and apparently the rest is cut off. If we could see the whole thing it would surely say “Sunazarashi” which is the Japanese name for sand seals.
I’d noticed this one a while back when perusing Creating a Champion. The two awnings in the foreground say very simply “Shops”. (Page 232)
I found the single letter on those scrolls in this rough design for Paya’s room rather amusing. It’s an “I” like the eye of the Sheikah. Did they do this on purpose? Of course it didn’t stay that way in the final design of the game, but I do wonder... (Page 260)
This drawing of the village front gate says, as near as I can make out “Hatenq”. That last letter bears much more resemblance to a “Q” than an “O”. (Page 265)
This little archway that fits in with all the designs for the laboratory says “Plua” but what that means I’ve haven’t been able to figure out. Purah’s Japanese name is apparently Purua, so that doesn’t quite fit. Do you have any ideas? (Page 269)
These Tarrey Town lanterns all say “Sakurada” on the sides, which thankfully is spelled correctly, unlike the sign for Link’s house. Of course in the final version of the game, the lanterns say “Builders” instead. (Page 290)
The sign above the sand seal rental concept art says “Rental” in Hylian letters. In the final game we have the same thing, but in Gerudo text. (Page 319)
In the concept art for Kilton’s shop, the Hylian says “Item Sho” which I imagine would have a “p” on the end if it wasn’t cut off. In the final game we have “Savage Swaps” instead. (Page 339)
And lastly, we have this flag that very obviously says “Goal”. I’ll have to go back to the game to see whether or not I’ve actually seen it in the game and just wasn’t paying attention, or maybe it doesn’t appear with Hylian letters. (Page 345)
And that’s all the Hylian I spotted in Creating a Champion or otherwise that was either different or that I hadn’t covered before. There were a few things that were the same, such as the doorway above the Hateno Ancient Tech Lab says “Laboratory” just as it does in the game. Let me know if you spotted any others!