The pre-patch event items should have been restored. When they were accidentally made soulbound, instead of warbound, when the event ended, they got removed from the WarBank. When they fixed it, mine reappeared in my bank, albeit in different slots.
Memory gear is no longer warband but bop - Support / Bug Report - World of Warcraft Forums (blizzard.com)
Sadly this was too late for me to withdraw them on alts and get them upgraded with remaining flightstones and crests, as they removed those too, along with the ability to upgrade them. Again, a lack of communication on their part, as I would have bought more as I went along and done the upgrades before release…