I have a bad headache, but I'll try to knock out a few now. I'll probably have to come back to this later to make it more readable.
I'm going to go in order of the ponies in the album, if that's okay. (VFY=since lighting and such can play tricks with colors, verify for yourself)
Sunny Daze (actually Sunny Daze II, but w/e) had one of the white bowback brushes, probably the creamier one since very early G3 plastics were seldom stark white.
Kimono (actually Kimono II, but again w/e) had a pinkish-violet bowback brush, slightly warmer and more vivid than her body tone. Bottom row, fifth from the left might be a match there, but VFY.
Spring Breeze was one of the '05 Spring Basket ponies, so that is probably where that other table came from, but her brush isn't pictured. (It's identical to Cotton Candy's.)
Bow Tie's brush is not in the picture.
Crystal Lace's brush is a pink flowerback, slightly brighter than her body color. Neither of the pinkish flowerbacks in your picture look like a match to me but VFY.
Bumblesweet's brush is a yellow bowback, slightly less golden than her body color. The one in the picture looks too light to me but VFY.
Crystal Crown's brush is not in the picture.
Butterscotch looks like she might the Berry Pickin' Fun version, in which case she came with a bright yellow flowerback brush, possibly the left-most one in the picture.
Minty's brush is not in the picture, although it look like it's in the bag of accessories in your album? Unless it's the next to last one in the top row, but that seems blue to me. IDK colors are weird.
Love Wishes didn't have a brush.
Bubblecup and her friends in the '04 Spring Basket came with two yellow flowerbacks, possibly the matching two in the middle.
Sunshimmer didn't have a brush.
Peachy Pie had a peach bowback, maaaaybe bottom row, third from the left is a match if it looks significantly more peach in person. VFY
Ocean Dreamer came with Summer Shores, so those glasses probably go with her. If one of the bluey-purple bowback brush matches the glasses, that's hers too.
Frilly Frocks has a dark pink flowerback, likely the first one in the bottom row.
Strawberry Swirl has a bright white bowback, likely the second or third one in the top row.
Triple Treat has a purple bowback, similar to her body color. Doesn't look like any of yours are a match to me, but VFY.
Blossomforth's brush looks to be the blue bowback third from the right in the top row.
I don't think Honolu-loo came with a brush...?
Waterfire's brush isn't in the picture.
Starbeam's brush could be the blue bowback second from the end in the top row, if it is in fact a soft blue and not mint green. VFY.
Guava Lava's brush is a golden yellow flowerback, likely the 8th one from the left on the top row.
Breezie we covered already.
Star Catcher came with a peachy-pink bowback, possibly 3rd or 4th from the left in the bottom row. The color should be quite similar to her hoof heart paint, VFY.
Wishawhirl's brush is the other yellow flowerback that matches Bubblecup's.
Whoooo, done! Sorry if anything doesn't make sense, I'm not at my best right now. Let me know if you need something clarified.