You can't "lock" something that doesn't exist.

[Averax]

"But you can stretch out and add pointy ears on a Hyur and call it a new race apparently. >_>"
"But you can put Kitty ears and a tail on a Hyur and call it a new race apparently. >_>"
"But you can put scales and horns on an Male Elezen/ Female Midlander Hyur and call it a new race apparently. >_>"
"But you can put Bunny Ears on a Female Elezen and call it a new race apparently. >_>
"But you can put in a Potato call it a new race apparently. >_>"

... You want to go on?

You say all this, but aside from Potatoes and Roes, Miqo'te, Au Ra, and Elezen all use a doctored up Hyur model.