User Manual Elgato 10LAC9901 Ring Light - Premium 2500 lumens Light

Yes, the Ring Light includes the Master Mount S.

Yes, the Ring Light may be controlled via the Stream Deck. You can create lighting presets to quickly switch up the lighting with the single press of a button.

Yes, the Logitech stream cam can be put on this light if the Logitech can take the standard screw thread of the camera ball mount.

It can be clamped to a desk

Yes, as long you tighten the joint it should be able to hold DSLRs + lens.

Yes it’s threaded to fit a standard tripod. Matter of fact the extendable stand that came with the light does not extend and another tripod is my only option.