A bit of behind the scenes, the initial version made me feel so incredibly bad I ended up adding sth to cover it up.
Then I also remembered that yordles don't have tails, so I think it worked out alright in the end.
You can look into this thread that tackles the same topic, but there doesn't seem to be a specific lore reason for how yordles look, perhaps it's just that champs like Tristana and Lulu were part of their own Megling race before the lore retcon: reddit.com/r/loreofleague/s/…
I mean, yordles always were kinda mixed design-wise, Veigar is closer to the type of yordles like Rumble and Gnar, who have cat-like faces. There is also Fizz, who is a fish, and LoR introduced some yordles who are closer to animals design-wise