Ooops. Forgot about time zones because it's now 5.10.55 AM Subeta time. I can't be sure if I did those quests before 5 AM

According to the news post dated August 29 "The following quest givers will be giving out festive items until 11:59pm on September 9."

It's now September 10 but I still got two retired items from the Shinwa quests I've done.

Same here. I'm not sure if I should continue questing or leave it be until staff comments on this.

I put the retired items I got in my vault category called Ticket Items. As this would be very tedious to keep doing I decided to stop questing until we hear from a staff member.