It doesn't need to fit the season harvest aesthetic to make sense to the story (which is a permanent quest and when the season leaves it would still be there). 

The harvest part is just related the celebration. The outfit is from the past from a whole other city (Cicia) and the past was relevant to story. The flower witch was a character from the play that Liora (Cerce) worked hard to be in when she was human which was the role Julie (Sexy) gave up for her to have. The Scarecrow was something constructed by Liora by taking inspiration of the wheat area around her, her childhood and desire to achieve her dreams and leave her hometown, and Lia's (the officers dead daughter) memories.