I don't think you need to separate the neutral and grounds here because this is a service entrance panel. The neutral obviously comes in from the meter can on the metal strap which does not appear to be isolated. It looks like it is bonded to the panel.
Len is correct; in this service entrance panel, neutral and ground are electrically identical and all the lugs are bonded to the panel. From a neatness and best practice standpoint, it would be best to use separate bars for neutral and ground. I always recommend this for main panels, so that they can easily be converted to sub-panels later if need be. However, if you really don't have enough lugs of various sizes to do this, it's OK to mix them.
No! It isn't Ok. That is why they have two discreet bars.
You would be correct for a sub-panel. But see above.
One is for "grounding" and the other is for "bonding" as I understand it.
Now you are confusing things. The ground bus, where the "grounding conductors" are connected, IS the bus where the bond is made. Not the other bus. IOTW, the ground bus is always bonded to the panel itself.
The other bus is the "neutral" bus and is for the neutral, or "grounded" conductors (how's that for confusing terminology -- one of the instances where you really have to know how to read the code). This is the bus which, in a sub-panel, is NOT bonded to ground. In a sub-panel that has been converted to a main service entrance panel, the bond can be made with a "bonding jumper" between the two buses.
One is the AC neutral phase
Again, this is very confusing terminology and not correct. "Neutral" is not a "phase" -- the phases are the hots, and the neutral is grounded (at the service entrance).
Just so happens that a earth ground by way of a bar driven into the earth is the AC neutral connection. At the pole, there is a Neutral phase coming off the transformer. That wire runs down the pole and directly into a bar that has been driven into the earth.
Actually, it is customary for the driven ground to be at the service entrance, not at the pole.
... but that neutral isn't in any circuit that is called two or three phase....in terms of it being a current carrier.
Also not true. First off, there really isn't any such thing as a "two-phase" circuit. There is single-phase, such as what your house uses, and three-phase, which many commercial and industrial buildings use, and also some campgrounds.
A 240-volt single-phase circuit, or a three-phase delta circuit, will not have a neutral. However 120/240 split-phase circuits and three-phase wye circuits do have neutrals, and these neutrals do, indeed, carry current. Three-phase in campgrounds will be the wye variety, and a 50-amp pedestal with have two phase wires and one neutral wire in addition to the ground. Unlike a 240-volt split-phase circuit, this neutral will always carry some current, even if the loads on the two phase wires are exactly balanced.
... Many RVs have a nasty habit shocking you if you get between the fram of theCode says "NO". They must be separate and stand alone. Either will serve as a neutral ground but there are differences. They both use different size wire.
... So I have a connection to two ground bars, a gas pipe, a water pipe, re-bar sticking out of the foundation and to three Electrical Metal Tubing runs that feed out the downside of the box. ... That is four ground connections per code and four more. I like overkill if it is free.
I think you may be misinterpreting the reasons for the bonding of the water and gas lines. These do not serve as grounding for your electrical system; in fact, it would be dangerous to use a gas line for this purpose. The reason these pipes need to be bonded to the ground system and to the driven ground is in the event that something accidentally energizes the pipes. For example, a faulty electric water heater might energize the water pipes; without the connection or 'bond" to the electrical ground system, no breaker will trip and the pipes might be energized to a dangerous voltage. By bonding the pipe system electrically, such a fault will complete the circuit and trip the breaker. Similarly, you want to ensure that all these systems are forced to the same potential if they come out of the ground in different places.
Hope that clears some things up.