How to connect interfaces' shields?
If you are not in a position to fully evaluate this then make connections to ground from the shields but via an 0603 footprint that can be optionally fitted with a zero ohm link or capacitor when the time is appropriate for making that decision.
Some ground connections may indeed require capacitors fitted (rather than a galvanic connection) and sometimes (ethernet particularly) I've see 1 kV rated capacitors fitted such as 2.2 nF. So, find a suitable footprint for a 2.2 nF capacitor rated at 1 kV and, maybe use that as the &quot;to be fitted&quot; component. But, for now leave them unfitted and test the board to see what is appropriate.
Leave your options open if it isn't too inconvenient!