Don't the keyboard and mouse share the same wireless dongle (the logitech stuff I had in the past all ran of a single unifying receiver) or is worse the new better?
I've got that webcam and it only needs USB 2, so it would make sense to connect that via the display.
So, anyway, you've got 2-3 not-too-picky peripherals, plus a USB hub, and 4 holes (2 in the display, 2 in the computer) in which to shove 'em, so you're comfortably ahead of the game and any of the permutations you suggest will probably be fine.
You don't need a TB3 dock for the setups you describe. If you want one, fine, but in most cases plugging in multiple USB 3 devices to a TB3/4 dock is functionally equivalent to plugging them into a USB 3 hub - and the peripherals you've listed don't even need USB 3.0.
Use a TB3/4 hub/dock if at least one of the devices hanging off it is going to be a display or fast thunderbolt device.
You've got 4 USB-A ports to connect your low-speed stuff and that leaves a spare Thunderbolt/USB-C port for a fast storage device- and either of the USB 3 hubs you suggest will hang off any of the Mini's USB ports to give you a couple of front-access USB ports.