Looking from the schematics for my -96 855 10V, it seems the Fenix 5.2 ECU can be both sequential and not. The schematics include the Motronic wiring - and there it says sequential, but for the Fenix it says multiport. But still there is one ground wiring to one pin each for each injector to the ECU.
I'm thinking this might be so that harness could be the same for both sequential and not. But I need to get it confirmed. Does anyone know ?