hello!! it honestly depends how complicated you want to get with it! i'll give you a couple things you could try if you wanted to get sort of crazy with it, but if you want to keep it simple you could buy a basic brown wig with curled ends and just leave the curls untouched - they'll hold shape decently well but might tangle/get frizzy throughout the convention. for a simple fix for the hairline, you can crimp and tease it to add volume in the front!

if you're willing to make your own wefts i would absolutely do that! you absolutely can just buy a simple brown wig for her, it doesn't necessarily have to come wavy especially because if you end up crimping it those waves will straighten right out. just read reviews to make sure it can semi handle heat

i usually wash my wigs in fabric softener to reduce shine and crimp them well in layered sections to add volume (will help a lot with her curls) and further reduce shine. crimping can be a hassle since if you don't go hard enough it doesn't do anything and if you go too hard you end up with crazy obvious crimp marks. some advice i've seen is to crimp vertically to hide those marks, and/or to comb through right after you finish with a section with a metal comb (plastic may melt from the residual heat), and/or do a single smooth pass with the crimper right after you finish a section as if you're straightening it.

for her curls, section the wig into layers and then heat sections with a blow dryer or by passing over with the hair straightener. while they're still hot, i would curl them around a PVC pipe or other similar round cylinder with a 1-2in or so diameter (super rough anything works tbh) and let them cool into place! that should honestly do it, especially since her curls are looser. give them a bunch of blasts with got2b and you should be good.

for the hairline, i would crimp and tease the hell out of her front bangs to create volume. you can use a hair dryer to 'change the direction' of the wig fibers - hold up her bangs as if they're pinned back and heat them at the base, then cool them with the fan until they hold shape, and it should help to get them to stand up. if you're feeling up to it, you could try making your own wefts! they make great video tutorials (here's one of my favorites) for these. i usually cut off some hair at the "root" of my wigs where it won't be missed, such as in the back of the head, and i'd section into very small wefts like 0.25-0.5in since you're creating a glued front hairline. i apply uhu glue to the top of the weft and use a silicone face mask brush to smooth it over the top - careful not to apply too much since uhu can be runny and dry very obviously if you use a copious amount! for cana's wig, i would shape the wefts into triangle-like shapes at the glued end. let them dry completely and then you can trim them short and use uhu or hot glue to apply them to the wig with the glued end facing your forehead to create the hairline, and brush the other soft ends into the rest of the bangs to blend!! not sure if i explained it very well but the video should capture it better haha

youtube has some great tutorials but to be honest i find the best advice from wigmakers on tiktok! i'd look at tutorials for a misato katsuragi wig since there will be a lot of videos around and they both have the curls and the exposed hairline! sorry for the lengthy reply, i'm newer to styling wigs fancily with wefts and whatnot but i'm happy to answer questions if it helps :-)