It’s possible to do the hand in this way?
Possible, yes. Easy, no. To start with, you would need to give all your cards a Can Rotate trait, allowing for free rotation. Then, you’d have to add an Irregular Grid to the Map Board, with one region for each possible card location, placing each region at the exact center point where you want the cards, and determine the correct card rotation for each region. Then you would use the Key Command to apply to all units ending movement on this map: option of your Map Window to trigger a Trigger Action on the cards, which would use a Dynamic Property to calculate the correct rotation based on the piece’s LocationName (which will now match the name of the Region it was dropped in), then apply that rotation to the Can Rotate trait.
No, you cannot have a hand splayed in front of you that floats in front of the board.
The best you can do is arrange your windows so the hand in on the bottom of your screen and the map above it.