My inclination regarding the second link is that the dress pattern comes from one source, and the sleeves come from another, or have been modified to add the poof at the top. The godets
may have been added as well.
The second cosplayer's (third link) dress looks bought.
Here's a Simplicity pattern
that has the correct seams and long sleeves. You would have to decide where to add a zipper if you use a non-stretch fabric, like satin. Shorten the skirt length, add godets front and back (for a total of 4), modify the sleeves
, and decide how you want the back of the dress to look.
For making something that looks just like the animation, some one who has experience making this can help more.