Thanks for all the feedback. Glad you appreciated the misdirect in 2, that was my favorite bit.
1. For what its worth... all blotted letters are actually there, under the blots!
2. Ah, good to know. It was meant to reference the previous puzzle's theme, astronomy. I'll see about finding a better name. Perhaps just "Signs".
3. Oh, right! I've been meaning to clue that a bit better. Any suggestions? I might add a second single-letter clue to a different blank, like the "A" clue. Or And I could add something to the last page like "Message received?" in green ink or "Message Received: [checkbox]" in an orange box.