I am making a very similar game. I had mine inspired by games like Baldur's Gate, so naturally I'm going with point and click. I also have an extensive HUD. Mine is probably going to be solely inside a castle though. I haven't decided yet. I've been working on it for quite a while, and it's been challenging. I haven't shown it off much yet.
I use both Modo and Zbrush. Modo has proven very helpful for this kind of game.
Anyway, yours is looking pretty good so far. Are you only going to use 4 directions? It felt a bit awkward trying to go straight in any direction since it only went in diagonals.
I finally got my camera set up in Modo so I can easily bring in isometric animated sprites with ease. That took a lot of work, but will be so nice and save me so many clicks. I don't even have to open the image in Photoshop before bringing into Construct 2 anymore.
My only concerns are memory use. This is why I'm going to keep the levels small. Since I'm aiming for a roguelike, this will make it easier to randomize as well. I believe Ashely recommend to stay under 500 (possibly 400) for max compatibility with PCs. If you're going for mobile, I figure it will be even harder.