I just got my Sony A7rii and have been playing with it for a day or two. One of the problems I encountered using Speedbooster/MC-11 adapter with my Canon lenses were auto-focus during video recording and also making full use of 5-axis.
So I ordered the Sony FE 28-70mm kit lens, which isn’t the best lens out there but it is super light (295 grams) and I can finally use all 5-axis for stabilization. FYI, if you use Canon lenses, you will either use the IS on the lens or the IBIS on the camera, you cannot use both at the same time and take full advantage of the 5-axis stabilization on a7rii. This would also work great with my Beholder DS-1 gimbal due to its lightweight.
In full frame mode, you get a very nice bokeh with the Sony FE 28-70mm and should be very good for vlogging. Plus you can get additional zoom range by switching from full-frame mode to Super 35mm and add ClearZoom for additional 2X, which almosts ends up in the range of 28-200mm! (One of the reasons why I wanted to get the A7rii.) Of course, the 28-70mm lens will be a good travel lens but for low-light stuff you will want fast lenses. I will probably be using my Sigma 24mm F1.4 or Sigma 18-35mm F1.8 for that along with Sigma MC-11 or speedbooster.
Check out this lens on Amazon – Link
Check out this lens on B&H – Link
Get the Sony A7Rii on Amazon – Link
Get the Sony A7Rii on B&H – Link