Well, blow me down!!
Mooncow, Candledave, Quisling - I stand corrected - although my primary justification for my interpetation of the first two words of the message - their occurrence early in the work doing exactly what is required - is correct, I'd missed the extra layer of cryptic clueing pin-pointing the starting points of the thematic characters in the grid. I'm in awe of them that noticed/deduced this.
And I'm still, like most of you, I suspect, totally discombobulated by the....(what's the word for a multiple, rather than a binary, ambiguity?) ...about what to do 'graphically' to represent the fate of the characters in the destination. Coloured pencils is one of the least dangerous...
APOPIYOM!
'Coming up, Sor. Will ye have a fast one while ye're waiting for the slow one?'