Ahh, these are actually a DLC that come with RPG Maker MV, so they're technically not part of the RTP. I may do them in future but unsure if I can make any promises for them. :>
Viewing post in RPG Maker MV RTP Shoulder-Up Portraits comments
Come to think about it, Degica provided me with additional download files when I bought RPG Maker MV so they might come from them, do you not consider them part of the RTP then, even if they are additionally included with the software when you buy it?
I know that everyone has them because I keep meeting them in games. :-3
Indeed, after talking with you, I checked my RPG Maker MV order's download files and the SF characters' portraits are inside Base Resources and their upper-body pictures are inside Extra Assets, just as you said. :-)
Oh, I see, they are not automatically added into new projects so they are not part of the RTP, that indeed makes sense.