Is this thread confusing dc negative with ground and using them interchangeably?
That's kind of inappropriate to do so and it has always driven me nuts that the industry has adopted the term "ground".
DC mobile equipment with a 12 volt vehicle and 12 volt components don't need a "ground" because the negative (which people are calling "ground") is itself at the same potential as the chassis.
My victron stuff for example is all 12v and has no enclosure ground of any sort. It does however have a 12vdc negative connection and this can be ran to a bus bar or any point on a 12vdc negative chassis.
Many times the chassis "ground" is rather poor but suitable upgrades can be done to provide a long lasting, electrically high quality negative path to your alternator and battery or batteries. I for example regularly run 90 amps through my truck chassis with minimal voltage drop, and what drop I do experience is from exceeding my alternator capacity.
If your connection from chassis to battery/alternator is good, then you can "ground" (not actually a ground but rather your 12vdc negative) can be done anywhere that is convenient as long as the connection point is free of paying and corrosion.
Some people will argue about galvanic corrosion but a car, van, or truck is not a boat.
That said:
If you CAN conveniently run everything to a single bus bar please do so. It makes life a lot simpler to have one really good chassis connection to this bar, plus a good lead to your batteries.
You always need a negative connection to your mobile equipment. You do not always need a "ground" because usually that's the exact same, electrically, as your negative lead as long as your vehicle voltage matches your power system voltage.
A 12 volt van with a 12 volt solar system means your negative and "ground" are exactly the same thing.
At the end of the day however, read the manual. Some devices may feature a small chassis ground in addition to a large negative cable even if the two leads are the same potential voltage.