Rexaar

The delay is there to give time for the server to save so item don't get lost permanently (99% of the time).

The description they used for this message is quite a bit lazy.

Try using the entrance using the dimension mirror in most towns.

If that don't work, write down the name of the last quest you finished here.

Meso and souls

Two ways to use it.
Press the Chain Arts: Maelstrom button during Chain Arts: Thrash second swing.
Press the normal attack button while holding the ↓ button.

All Elite monster/champion at Vanishing Journey, Chu Chu Isalnd, Yum Yum Island, Lachelein (and most likely all area outside the arcane river) do not drop medal of honor.
Elite monster/champion start dropping medal of honor starting at Arcana and all higher level area afterward.