I don't know if you're super brand loyal, but I am going to use Aphrodite in white from EpicCosplay
The mannequin doesn't make it look that good, but if you scroll down to the actual person wearing it, it looks like it could work for Periwinkle quite nicely, plus it already has the longer bangs in the front ^-^
as for the styling, a lot will be backcombing the top to get it to look nice and tall, then keep a layer to smooth over the top, spike the rest of the wig up (using got2be glued blasting hairspray, and maybe a little got2be glued style freezing gel on the tips)
Don't forget to blow dry the hairspray while still wet to get the style to "set" in place.
Hope this helps!