Goodly

We're having issues with webclient downloading textures from our texture host right now, should be resolved in a day or so

Why did you check the option that allows you to see servers that were hidden by the admins and then complain that the admins didn't take action on it?

Yes. Like I said, the skins on AlwaysClassic are coming from minecraft. Incorrect. Again, the skin for "animal" you're seeing on AlwaysClassic comes from the Minecraft account named "animal", which you can see is the same here: https://namemc.com/profile/animal.1

i like how we both had similar ideas about formatting/comments

namemc only lists official, paid Minecraft accounts. It has nothing to do with ClassiCube. The point I'm trying to make is that AlwaysClassic is only displaying Minecraft skins, not ClassiCube skins. It's trying to find a skin for the Minecraft account named "matelo2", but there is no such account, so it shows the default of steve.

AlwaysClassic is probably automatically setting everyone's skin to match the Minecraft account of their ClassiCube username. This is something you'd need to ask the server owner to change, but it's unlikely they will. See how Animal's skin matches the Minecraft account here: https://namemc.com/profile/animal.1

As far as I know, no one has plans to make a singleplayer plugin that does these things. EDIT: Singleplayer has the ability to create and edit blocks using /blockedit

Everything you've mentioned is possible using servers. There are no plans to bring more content to the singleplayer experience.

There are no plans to add any more models to the base game

Cows are not in ClassiCube unless you install https://github.com/ddinan/more-models or the server has custom models plugin and someone uploads a cow model.

In truth it was just not added because it was complex. My opinion there is entirely my own (I'm not in control of the site features in any way)

I'd go so far as to say that pinging the website to determine the skin type would be a blunder, and was a blunder when Mojang did it. It makes much more sense for the skin file itself to be what determines the arm type, because the skins must be made specifically with one or the other in mind. They are not freely compatible between each other as it might seem if the user was allowed to choose the option when uploading.

I don't know. It probably is, but you shouldn't need to ask this, as the setting should appear by default in the properties file. Modify the existing setting rather than adding a new one