Okay. So kokoro 16 is a woman and a native English speaker, right?
Your explanation of the context and background in #3 made things clear.
The guy just wanted to write "Good night. Have a nice dream ❣ " in Japanese.
良い夢を❣ is not a common traditional Japanese expression, so I strongly felt it as the "directly-translated style Japanese."
And I didn't know why the writer intentionally chose that style, which seems a little bit funny to my ears in a certain viewpoint.
But now it's clear that he wanted to write "the typical parting greetings of English" in Japanese.
As Japanese, or as a non-native English speaker, I think "Good night. Have a nice dream!" is the typical greetings in English, no matter if it's not true to native speakers.
He didn't think he could convey something more than the parting greetings, I bet.
The last ❣ may convey his positive feeling to you, but it doesn't necessarily mean that he wanted to become intimate with you.
But I don't know what he is thinking about about you because I'm not him.
Apparently, he wanted to be a good friend with you. But we cannot guess he wanted more than a good friend or not.
Hope this helps!