As the post described, Cuphead is going to arrive on February 24 alongside a special emote, and Mugman will join the fray a bit later, on February 27.
The costumes can be purchased from the in-game store. Five Crowns for each costume piece, same for the emote. So for this time, if you want to collect everything, it will be 25 Crowns in total.
Check the image below. What do you think, will you get all the pieces?