The thing about the seals is that they have no purpose other than to give you access to the relic quest, so my guess is they will still be used unless they decide to give them another person. Like the above poster said though, the seals are the least of your problems, especially if you want to get a relic before the servers shut down. Ifrit alone takes about 1-2 weeks to master on average for a typical linkshell so time is probably your biggest enemy at the moment.