i would say it's a moon shaped tip - like a 401 or 402. they are very pretty, good luck and definitely post if you decide to make them!
I am pretty sure it is a Wilton 100. THe cupcakes are nice. Something different from the usual swirl. I might give these a go also.
I agree it looks like the petal tip you just have to make ruffles with it. It's very pretty, makes me wish I could make ruffles but mine look awful.
looks like a 366(leaf) to me.
Thanks for your suggestions. I will have a poke around my tip box and see if I have any of these tips, and if not, maybe it's time for a trip out to Michaels!