Given it's XDA profile, there's no sculpting dictating what row the keys belong in, so if you can find enough 1U keys that you're happy with using as modifiers in that set then it's already Ortho (and I am kinda thinking about getting it even as-is for my Preonic-sized split)
Yes. K6 is a normal 65% keyboard and this set has a 1.75u shift, so it will fit on the non-standard right shift of the K6. This is also compatible with 67 key boards like the NK67 Entry or the KBD67 Lite.
Dye Sublimation. This can sometimes cause blurry legends but its rare, and when it happens it never looks unbearable, simply like a blurry set of double shot keycaps. The way dye sublimation works is they make the blank keycap, etch out the space for the legend with a laser, then pour dye into the hole. They then heat the cap up so the legend stays. Overall it sounds sketch at first but I've had some amazing dye sub keycaps.
Hope this helped!!