CCR: Question regarding a specific fanclub

First of all, I couldn’t find a CCR subreddit, so sorry if this post should be somewhere else.

So, I missed Sephiroth’s fan club on chapter 5. Then on chapter 6, I finished A LOT of missions, thinking I could go to the park in chapter 7 and get Sephiroth’s fanclub invitation. Doesn’t seem to be the case, though.

Is there any way to get in after chapter 6? Otherwise, my plan is to just finish the game getting everything else I can, including all missions, and then going back to my chapter 5 save file and finish the game doing all the fanclub stuff. Is this my best possible approach at the moment at getting the fanclubs and mail throphies?

Thanks in advance!