Single-point ground vs multi-point ground - large DC system
In either situation, one device could be taking a large current and producing a significant (and noisy) volt drop down its return wire. If the return wire (at the device) is also a reference node for digital comms, then there would be chance that some device load currents can also flow through the comms interconnections and cause havoc with data. The noisy device currents would not take this route if there wasn't a volt drop of course.
So, the comms are potentially likely to suffer without some form of galvanic isolation or, a comms system with a high level of common-mode noise resilience. Whichever you choose you need to stop noisy device currents partially flowing back via a route that they are not intended to follow.
All the above words are about trying to keep your comms data intact. As for power, individual cables might be better but once you have the comms problem sorted any method would work providing that you do what I suggest for the comms and, at a risk of boring you I'll repeat/add: -

Galvanic isolation
Differential signalling
High common-mode resilience