I like it! I'm in the same boat, living in Florida, so linen it's going to be for me aswell, haha. I've also only sewn maybe two/three things before this, so I'm hoping it goes well enough.
And, to put some curiosity to rest about the black "Epilogue Dress" I took a screen cap, and also cropped it down to where it only shows Merida wearing the dress, for study:
I think it is black, when you look at the highlights on the fabric, they're relatively colorless, and it seems like a velvet fabric. It has the same wide belt and detail at the bottom of the dress as the art does.
Also! I forgot to add. I immediately pestered Arda about their Merry wig, lol. They don't have Merry listed on restock yet, so I thought it couldn't hurt to ask. I was told that they won't be getting the Pumpkin color back into stock for another 4-6 weeks, but! They are also currently working on adding another color variation of Merry soon, that's close to Pumpkin. They just don't have pictures of it yet.