Gaming

Probably, yes.
Would at least be reasonable for a mage play-through...

Magic horses are very useful in my work as a professional Thief Assassin Mage Rebel Werewolf 

Maybe I should have considered that I don't need 26 bottles of frostbite venom with me wherever I go, before I left my cottage...? I guess I can sell them, though, as I am already storing more at home... But the Bruma welkynd stones (which are listed as potions) could certainly have gone into storage - I probably don't need 12 "refill your magicka completely" potions any time soon. Probably.

Scamps!

Also, my horse must be dead because it disappeared when I really needed it and I went looking around the area where I'd left it for ages with no luck. Then I borrowed another from the stable, because it wasn't stealing (red), and now that horse keeps fast travelling with me just to immediately walk off.

I'm considering killing it

Try using that excuse in real life.

"Well there was nothing on it that said taking it was stealing, so..."

Some khajiit argue that way. You have to write your name on it. Otherwise it's free for the taking.

This one knows. They are also pretty good at knocking things off of shelves and tables. 

and cuddly