Well... I managed to buy get everything I need for both /yawn and /sleepy.
When I went ingame to showoff test these new emoticons, it turned out I can only use /sleepy, and /yawn wasn't working.
I checked my collection, and it said I have both sets required for both /sleepy and /yawn, though only /sleepy showed up in my collection.
Is this intended or is it a glitch?