[Mechanical Design] Regarding the gear mechanism for a human-powered "coffee cup" ride

I am planning to build a human-powered, bicycle-driven "coffee cup" ride for a school festival and am currently designing it using Fusion 360.

My current concept involves a central gear driven by the bicycle input, which transmits power to four surrounding gears.

However, since the gears are positioned slightly above the rotating platform, I am unsure of the best way to support the shafts for each gear.

Additionally, the current design only drives the four surrounding gears; it lacks a mechanism to rotate the platform itself.

I would appreciate your advice on the following points:① Is power transmission actually feasible with this gear layout?


② What is the standard method for supporting shafts and bearings when the four surrounding gears are elevated?

③ What kind of mechanism should I adopt to transmit power from the central gear to the rotating platform itself?

All four surrounding gears are currently designed with 16 teeth (16T).

*Since people will actually be riding this, please also point out any potential safety issues.

I have attached images of the Fusion 360 design.

P.S.
I am Japanese, so I am not very good at English.