Oooh what a variety! Sundance is quite elegant! I love her cutie mark. One suggestion, do you maybe have something smaller to hold her braid? The pink hair tie is a little distracting. Her colors are spot on! Sadly, I don't think using the Blossomforth head will increase her value because of bait rarity, but it is a fabulous choice! Having her symbol on both sides is a great idea and makes her worth a little bit more as some collectors prefer that.
Lighting Strike is one of the loveliest fakie custom I have seen! That dyed color is amazing, as is her hair!! The detail work around her eye is my fav part!
Black Widow is a pretty girl. Her little spider webs on her hooves are a fabulous touch!
As for prices it can really vary. Typically people won't pay as much for fakie customs, not sure why honestly, so your best bet might be to take offers. Good luck on your sales, they are lovely!