I expect you could begin work on a skin but of course you won't see the changes ingame yet. The files 00000020_Hud.dds and HUD2.dds from the default textures folder seem to correlate to KR somewhat, so perhaps you could run it through that as an onscreen test.
As for code mods, seems a lot of the power is going to be in the Command macro. We might see a different approach to code with some of the extended functionality in macros without the need for a lot of fiddly additions/updates to mods.
Looking forward to seeing what the modders come up with.. if I have time when modding is allowed I'll port my skins over from KR to SA. I did lose the source for Nautical however, got wiped between backups, so that may take a while to re-create.