I’d create it in ‘full 3d’ - It’s possible to have a static camera. (Even an orthographic camera could be interesting)
I spent 10mins noodling with the idea and this is what I came up with:
(For a BP to receive keyboard input it needs to have a setting changed (Red Circles))
This example will rotate in both directions, but the main idea is to show an implementation of ‘Rinterp to’ node.
My idea as far as blueprint communication goes - Instead of the ‘R key’ you’d have a “Spin the wheel” function (“Custom Event node”) to control the spin and generate the result, then to pass the ‘wheel result’ to your paytable calculator: you’d create a function/custom event in your paytable with an input (and maybe an additonal input telling the paytable which of the 3 cylinder is sending the info).
Tangentially: I wonder about what sort of things a slot machine inside of a 3d engine could do that would be impossible otherwise. (Not sure if that’s a direction you’d want to take it, but ‘Pushing the medium of slot machines into its next evolution’ is where my minds at. 
)