Hello Mukikois52
Welcome to the SBB Community.
Is it possible to add the tickets back to my account so I can manage it?
No, this is not possible.
You are welcome to purchase Supersaver upgrades and seat reservations even if you do not have your ticket present in the SBB Mobile app; simply show the latter from as PDF or out of your e-mail inbox together with your physical passport.
The ticket, the Supersaver class upgrade and the seat reservation are three different independent products which you can purchase each on its own; there is no ticket needed to legitimise the purchase of a class upgrade or seat reservation.
Conderning the seat reservation, we might have some interesting insights for you in this blog:
https://community.sbb.ch/blog/23887-demystifying-seat-reservations-on-swiss-trains-a-comprehensive-guide
Kind regards,
Roland