The answer is yes, you can mount the D string in the A position, and there's no harm to the guitar.
Here's some perspective;
Years ago, I went to restring one of my guitars, but didn't have a complete set.
What I did have was a lot of odd string gauges, and all of them light, unwound.
So I strung the bottom three strings normally, i.e.; G, B, and E.
Then I strung the top three strings with what I had laying around, but in essence, G, B, and E string gauges again, only tuned up quite high to achieve the conventional tuning of E, A, and D.
It sounded really interesting, and quite sparkly.
I showed it to a more seasoned player a few days later, and he chuckled.
"You know what you did, right? You restrung your guitar in what they call, "High strung" or "Nashville strung". It's what some record producers use in multi-track recording to double the main guitar track, but to give it a higher frequency. Makes the record sound richer."
Good stuff.
It's all good.