Necessarily speaking, I believe these would be great ideas
First, I believe that having more donkey and mule varieties would broaden them up a bit! The horse markings are their own texture, making it possible to put them on donkeys and mules as seen in the two images below.

Another thing I'd like to point out is that only a male donkey (jack) and a female horse (mare) can make a mule. Breeding a female donkey (jenny) and a male horse (stallion) will make a hinny. So in my opinion, it would be nice to see Hinnies in Minecraft.

This kind of suggestion is better suited to our discord's #suggestions channel, rather than our issue tracker.