References

Saw the alpaca and inspired me to do my own so might as well give feedback in exchange for the inspiration. I feel that you're sticking to much to the IRL proportions in the alpaca ones instead of experimenting with them. Some shapes are a bit overly complicated, you can go for a single simple shape for the woolly parts instead of doing several curves, like in the example I'm posting.

I think you're repeating feature shapes a bit. So for example, 3 out 4 of your buffaloes have the exact same eyes. Something that helped me avoid that were the sushi chefs that Stan showed. You can look for examples at Dragon Ball, Goku tends to have rounder eyes (when he's not serious) which make him look friendlier while Vegeta has more triangle like eyes that accentuate his seriousness and aggressiveness Another thing I notice is the lack of proportional changes (I'm also guilty of this). The relationship of size between the heads, eyes and horns feels the same. This relationship tends to have an impact on the character for example bigger eyes in comparison to the head accentuates cuteness and frendliness while smaller ones accentuates seriousness. For example, you can do big horns, medium head, small eyes or big eyes, medium head, small horns.

You need to think about the bigger picture, you went in for the smaller details. For example if you trace a straight a line from the the (your) left side of the skull's jaw to the brow ridge, you can see that it is more tilted than the actual photo. If you get those big measurements first then you can move to placing down the most relevant lines. The nasal cavity could've been simplified, you have a wobbly line on the inner side that could've a simple straight or S curve.