Sensei PRO 55-62mm Aluminum Step-Up Ring

No, the Sensei PRO 40.5-52mm Aluminum Step-Up Ring will not fit the front thread of the Fujinon X30 camera because the front thread of the non interchangeable X30 lens is an unusual 40mm, not 40.5mm. The FUJIFILM X20 Lens Hood and Filter Set for X10, X20, or X30 Camera: https://bhpho.to/2WTA0sh features a step up ring 40mm to 52mm. It is the only step up ring that will fit the front thread of the Fujinon X30 lens.

This item is manufactured in China.

Yes, the Sensei PRO 58-67mm aluminum step-up ring comes in a clear protective case.

While it would depend on the lens and filter you are using to say for sure, since this is a step-up ring and even wider, it is unlikely that it would cause any vignetting.

The OD is probably 79 or 80mm. You will have to try it with your cap, This is never an exact science due to the fact that dimensions are never precise from cap to cap and ring to ring.

I think they should work fine. The base magnetic plate from Freewell should just thread into the Sensei step up ring. It looks like Freewell also makes step up rings that work with threaded and magnetic filters. (See 2:10 at the link below) https://www.youtube.com/watch?v=JX9VY4oxOis&t=150s

The pro ring has knurled edges and a hardened matte black surface for minimal glare and reflection.

The Sensei PRO 39-49mm Aluminum Step-Up Ring will fit on any lens that has a 39mm filter thread. 39mm is a common filter thread size for many Leica lenses.