In general, iPad's with USB-C can connect to our Thunderbolt docks, but the functionality will depend on the specifications of the USB-C port on the iPad.
All iPad's with USB-C will be able to be charged when connected to a dock with power delivery.
In general, iPad's can support up to one external display when connected to a Thunderbolt dock. Resolutions and refresh rates depend on the model of iPad, as well as the docking station model.
iPad compatible USB devices and peripherals (mouse, keyboard, storage, Ethernet, etc.) can be used with the dock. The USB-C port on the iPad can vary from USB 2.0 to 40Gbps Thunderbolt, so note that transfer speeds on the downstream USB ports will be limited based on the capabilities of the host port.
iPad Pro's with the M-Series chipset support 40Gbps Thunderbolt, which means that you will get the most functionality out of a Thunderbolt dock connected to these iPad's.