I have a couple limited 5* Blooming Dreams, Crane outfit and almost have the new balloon outfit but I have not needed them for Mira Crown I have used the 4* ability outfits and my 1st limited outfit most. You can absolutely do it with free outfits you just have to glow up fully and match the affix properly the only 2 stages that are based on the current banners is the last two and Honkai Star Rail also does the same thing and base the current endgame mode on its current limited characters. This is nothing new and as I said before this Mira crown I used recommended button with mostly 4* outfits and had to glow up my Swan (standard) 5* outfit to beat level 7
