I have not used the video functions extensively on all of Sony's alpha series cameras but I'd say either get the GH5, A7SII or A7III if you must shoot with the above models. Spec wise, the GH5 is a fantastic camera in the studio since it shoots 4K, slow-mo and the whole shebang. I have not used it for run and gun video before at all. The A7SII has fantastic low light performance so it'll help when it gets dark. Shot a short film last year on it and the video quality is superb (esp if you don't mind colour grading the footage afterwards). The A7III should be pretty comparable with its newer specs.The A9 and A7RIII are more tuned towards photography in my opinion.
Lens wise I'd say get something that's image stabilised with a longer focal length. Something like the 24-105 f/4 G will pair nicely. Reason being those two lenses mentioned aren't stabilised so you may need to carry a monopod around for more steady footage. Otherwise if you very buff and have good balance and control of your core and arm muscles then can handhold la
My opinions above are based on assuming that you at least have a moderate level of understanding of how to use the cameras (exposure, focus etc.).
Just a note on my personal choice though. If you ask me what I'd use to shoot video, especially for a wedding, I wouldn't use any of those above. I will rent a Canon XA35. Sure, it doesn't have 4K, f2.8 aperture, or a full frame sensor. But it is way more compact, easier to hold, and has much better battery life than any DSLR or mirrorless camera can offer. I can get around to tight spots to shoot because it's small and light. I can just carry 1 spare battery; 2 batteries will last me half a day of non-stop recording. It has XLR inputs for a better microphone to give better audio. Most importantly, curious guests won't come over and disturb me and ask "wow that's a nice camera is it expensive" because it doesn't look as "pro" or intimidating as a video rig would. Less thinking about these other things gives me more time to think about what's infront of the camera; how to frame my shot, how to position, how to account for lighting conditions. These are the factors that ultimately allow me to get better footage. Just my 2 cents.
Edit: the current model seems to be the XA11/XA15.