Yes,changing icon,nameplate & frame is possible.
How to change
Download something which could read dds files.(I used sagethumbs since i couldn't get dds viewer to work)(btw sagethumbs would make preview appears for any picture files so it's kind of annoying)
Go to maimai\data\sprite
If you would like to change icon then maimai\data\sprite\collection_icon and so on.
I'll use icon as example.
icon0000_simple is the default icon so just find other icons you like and replace with that name.(Just make sure you make a copy in case anything happens)
Steps are then same for nameplate & frame.
Hope this helps.