Ooops, I thought I had replied your message but it was another person. Sorry! Currently I'm not working on DarkDiamond because I have too many things to do, so there'll be no new beta this Christmas. However, as I don't want DS hacking to die, I've decided to develop SDSME so DS hacking is available to everyone in the world
No! Of course not! Obviously I'm still working on DarkViolet. However, I'm fine with you using the HeartGold hack as a base for a generic Red/Blue DS remake, but you are not allowed to call it Pokemon DarkViolet, because it is my hack.
The screenshot you have is from a really old base when I was working on Pokemon Emerald, and not only that, but that's Viridian Forest, not standard outside grass. Viridian Forest will look similar to the screenshot you posted, but the overworld will look like the pics in my signature.
And no, none of my screenshots are mockups. They're all actual screenshots.