Yes, the plate that comes with the Ronin-S will fit on this tripod head.

This kit includes the Vidpro TC35 Tripod Case, B&H # VITC35. https://bhpho.to/2AyGkMS

Yes, the Manfrotto MVH500AH Fluid Video Head with Flat Base can be mounted and operated on the Manfrotto 681B Professional 3-Section Aluminum Monopod.

The staff's answer seems to contradict the answer of April 18, 2017 to a similar question, where a staff member says you have to level [not by the column] " the old fashioned way, one leg at a time".

Recommended tripod legs for the Manfrotto MVH500AH Fluid Video Head with Flat Base should be able to handle 17.6 lb or less.

Amazing head for the money. Surprisingly smooth. Have used it with a Canon 7D MkII + 100-400MM Zoom (MkI). Approx. 5.5 pounds total. Tripod had vibration (due to wooden platform, people, sea breeze, who knows,) but got Sea Lions with acceptable pan smoothness later. I think you have 5.5 lb. spring, plus can compensate by tightening head rated for maybe 11 lbs.

Yes. I have the Manfrotto MVH500AH flat base video head attached to a Manfrotto 520ballsh 75mm short half-ball mounted on a 75mm half-bowl tripod. I do not use any adapter between the video head and the half-ball. The video head flat base is slightly smaller in circumference than the flat top of the half- ball but the three set screws in the half-ball to prevent slipping anchor just fine against the flat base of the head. The video head stays securely on the half-ball with no twisting at all. When attached, you have to look very closely to even notice the slight difference in circumference. Works perfectly to level a camera for both video and photography.

A bubble level is included and it is a great option for that camera.