Hi Meena,
Have the affected guild members checked the realm list sorting as mentioned here?
If it’s not due to the realm list being sorted incorrectly and their characters are still missing, please ask them to post a reply in that thread so we can have it escalated to be investigated as soon as possible.
@Helizabel - no updates on the discrepancies between the “old” Guild interface and the “new” guild interface just yet. But it is being looked into 