Consider exploring a Floating Pawn Movement component (for collision purposes) and mirroring a vector:
Or, if you decide to go down the Physics route, disable gravity, constrain to a plane and counter friction & impact energy loss with a physical material. Great potential for uncanny behaviours but can be fiddly.
edit: consider this a brick candidate: How to add a hit count (health points) to individual instances? - #2 by Everynone in case you need a breakout thing.