Reddit mentions of Women Lady Fashionable Silk Long Soft Peacock Scarf Wrap Shawl Stole (Black)

Omg, this looks like SO much fun! I'd love to help somehow! Amazon shopping it is!

Flower crowns:

Red flower crown

Purple flower crown

Smaller flower crown

Pink flower crown

You could also hit up a local flower shop, or maybe if a relative/friend would let you pick some flowers from their garden, you could make a braid crown in your hair, leave some hair tendrils down for the ethereal effect, and just weave the real flowers (and maybe some lacy ribbons?) into your hair.

Clothing: I get the really flowy vibe here, so I'm thinking some kind of kimono/shawl/duster would be perfect to go with your theme.

This shawl would be really pretty

This shawl would also be really pretty

This Sarong would be really pretty too

Shoes similar to this would be perfect I think! If you have any discount shoe stores near you, like the ones in the mall, you might be able to catch them on discount around this time. If you don't want to splurge on shoes, you could easily turn a pair of your sandals into a shoes like this by just tying some similar colored ribbon in a criss-cross pattern around your ankle and up your leg.

I also feel something like This would be super cute, especially if you didn't want to wear clothing that shows a lot of skin.

Not sure how comfortable you are with revealing items, but I really feel like the bra from This set Or the black version might be better
would really compliment the look you are going for. Maybe wear some nipple covers, or a nude bra under to hide things, cover it up a bit with a sheer shawl, and maybe a sarong or some shorts on the bottom?

Maaan, if you lived closer I'd totally let you raid my closet! You could probably find most of what you need!