They sat back and waited for a human being to take the bait and reply. No.
In both case the replies came from the two separate individual users the creator had messaged.
The creator chose them
The creator instantly opened their manual wallet, drafted a response, and hit broadcast. ????
they just had all the time in the world to wait. ??????
Today, a second user stumbled into the trap. No. The second user was selected.
You said yourself, it was entirely planned.
(The creator posts regularly, normally and cryptically)
They had 3 minutes of real-world preparation time. <-
The creator saw the notification... (then what, magically)
They manually opened their blockchain wallet.
They manually bundled their texts and the pixel-art image into a single multi-output transaction bundle (which explains why the final pieces land on the EXACT same second).
are you even listening to yourself that is impossible