Hook it up with just a Thunderbolt (TB) v2 cable or DisplayPort/HDMI cable? No.
Buy a TBv3-to-TBv2 converter probably.
Most likely this will be a "one input" port wonder just like the original Thunderbolt Display (docking station) and the two UltraFine displays
USB Type C 4K https://www.apple.com/shop/product/HKMY2VC/A/lg-ultrafine-4k-display
TBv3 (Type C) 5K https://www.apple.com/shop/product/HKN62LL/A/lg-ultrafine-5k-display
If there are 1-2 displays they'll likely just be TBv3. The 5K UltraFine has a choked down ( lower than native resolution) mode for the Mac Pro 2013 now. It wouldn't be hard to put it on another monitor built to Apple's requirements.
I think folks are fooling themselves if think the monitor Apple is mentions is solely
being constructed just for the new Mac Pro. Extremely likely it is not. Doing service as docking station for the vast majority of laptop line up is probably another role it will be tasked with.
Also likely Apple will skip the use case where multiple video sources ( more than one computer and/or TV source ) is hooked up. No built in Keyboard/monitor switch. Same thing with buttons or controls on the monitor. Likely none.
IMHO, the better fit would be a 21.5" 4K model that has Thunderbolt v3. ( The one port wonder MacBook is now a screwball corner case that really doesn't deserve a targeted monitor at all. ). If the MP 2013 needs a full resolution, native 5K monitor there are already options out there. Apple probably isn't going to try to sell every monitor type to everybody. One, maybe two, monitor docking stations and that will be probably be it. ( and those will probably leverage the iMac screen options. Basically the same panel and controls. )
You can get something. You just don't get full native 5K bandwidth.
Two THunderbolt cables to the same device from the single host isn't a viable option for non monitors either.
There would be a solution if Apple had a monitor that had a "non docking station" mode and multple inputs. For example, One Thunderbolt 3 , one HDMI , two DisplayPort. That would work. Apple probably won't build that though whereas several mainstream monitor makers do.