We met her Friday. Park opened at 9 and app showed her meeting at 9, so we went there first. No Moana, "check back in about 30 minutes and we'll know more; she should be here within the hour." Went on Haunted Mansion and came back, I think it was a little after 9:20, and a small queue had started. Someone told us they were saying she'd be there in 10 minutes. We were maybe 10 groups back? At 9:30 they opened the inside line and I assume she started meeting. We met her at precisely 9:45 according to the photo time stamps.
By the time we got out of line, it was full, and it was pretty busy every time we walked by for the rest of the day - but Friday was a very busy day in general. I'd think next week will be better...