Yes, and yes with difficulty.
The 3D aspect of the plane and the army elements are relatively easy – every layer can be turned into 3D but that layer is simply a plane or a plane with a mask that you can use a camera in AE to move around. So you could make a 3D battlefield and populate it with an army that stands up on that plane.
To get the curved elements like the shields you can either use something like Element 3D which brings 3D object functionality to AE or cheat by using CC cylinder or sphere to add a curve to the flat 3D objects.
The other issue is that the 3D layers in AE are flat so as you move your camera about (say, on the spears) unless the spears are also rotating, at some point you are going to see their edges and they will disappear (a plane has no Z dimension – Imagine arcing the camera down from an overhead shot on the battlefield. When you get to the ground level the plane of the battlefield will be edge-on and virtually invisible.)
You can use expressions to keep these elements facing camera so it gives the illusion that they have volume.
The last issue is the infinite world – because the battlefield will be a rectangle and a plane, the back edge will be visible at some point at low angles because it can’t go on forever. You can use soft masks back there and some haze to let aerial perspective to its thing and wash out the seam between ground and sky – its how the world works anyway. You can thank water vapour in the air for that. Or do what they did in your example and not have a a ground plane, but I find the static BG fights with the illusion.