Inventory GUI to Canvas(world frame)

#1 I had an idea about this when I saw your other post about this a few days ago. But I never said anything or even tried my idea. I can't think of a resource that actually does this so you will need to to implement the "throwing" of the object once it leaves the inventory container yourself. The drag and drop inventory gui is probably a good start for this - which sounds like what you've got now, but I have never checked it out.

What you would need to do would be to determine if you are trying to release an object from inventory into the world. Maybe, on the mouse release action, if it finds that you are not trying to place anything in another gui inventory slot that it instead finds the screen space coordinates of the mouse. You can then spawn the object and drop at the player's feet if your mouse was at the bottom of the screen. If at the top you would "throw" it with variable impulse depending on the distance from the center of the screen. Same thing for the left and right sections of the screen. And only do that if the mouse release isn't over another inventory slot.

I would start by examining the existing item throw and toss scripts just so you know how to create and impulse dropped objects - that's the easy part. The tricky bit will be converting the mouse position into vectors to be used.

#2 Some level of the DragDropGUI is included in TGEA 1.7 according to Dave Young's post here. That wily Dave also notes how to use it in his post. You will have to work on the constraints and "throwing" into the 3D world, though.