Responding to my own post - I will say the MBP + Belkin thunderbolt 3 dock + Ultrafine 5K is elegant and trouble-free. My original query here was mostly driven by the amazingly bad review comments for the dock and monitor (user reviews seemed to be terrible - pro reviews were not that bad). There is a latency issue with the connected Magic Mouse - it's "sticky" and won't release elements as fast as I seem to need it to - often I've moved up to the menu and inadvertently dragged an element up there as well - haven't done any troubleshooting to track this down. But as for the display I have no complaints.
