Another vote for oilcloth, particularly if you have small children. We had an extra piece that we put under my children’s high chairs when they were small which made cleaning up the floor much easier (DS could distribute food over a very wide area…). Definitely get the table protector stuff to go underneath it though, you can buy that online cut to fit.
Shoes: Dr Marten’s Chelsea boots work most of the year. The fleece lined ones are so warm. As seen on several of my colleagues at work. Failing that, silver trainers - again a style much modelled by my work colleagues.
Riding coat: yes yes yes, you will thank yourself for it. DD has the Equidry and loves it. Borrow whatever you are going to buy and check that your horse is OK with it as I’ve known ones that don’t like the flapping behind them; the straps on it should secure it just fine but it’s worth checking before you splash out on something that turns out to be a Horse-Eating Monster.
Tupperware: Very random collection so I am very envious of those of you with organised and co-ordinated Tupperware. Lids have a box of their own and are sorted by size. Boxes are stacked as far as possible. No-one else in the house can put any of it away the way it should be but then I have the opportunity to sigh woundedly and dramatically at everyone as I fix it. Actually it mostly works.
Goth decor: DD also wanted black/red at around the same age and we refused but gave her otherwise free rein of the colour chart for a feature wall. If you do go with it, Polyfilla do a paint that is the only answer to covering it up when she goes off it, other than wallpaper.
Drying towels: if you can get a towel radiator then do. You can buy freestanding ones I think.
Sunburn: Aloe Vera gel is the best thing but any moisturiser/lotion will do to try and get some hydration back into the skin. Put it in the fridge to make it extra cool as that helps too.