Bruce..........

"I am being told that because the "House Batteries" are requesting a charge from the Engine alternator to keep the house batteries at a proper level to service the house draw."

Bogus.

"If the Alternator or the regulator is not functioning correctly it appears that one or the other is creating an over voltage (which is tripping off the ABS computer my other problem) ."

That sounds very reasonable, with my money on a bad regulator.

"The final condition is the fact that the generator reduces the voltage dash meter from 29V. to 25V within 1 minute after starting the genset."

Here is where the communications are breaking down. Is the engine running when you start the generator? If so, which voltage are you describing? House or chassis?

Let's do a quick system overview. When your engine is running, with a properly functioning alternator and voltage regulator, both the house and chassis batteries are being charged and because the alternator is so large in terms of output it can handle almost any resaonable load and you will see no difference in the voltage.

With the engine still running, if you start the generator, and the inverters have been left on, the generator power is seen by the inverters, and both the inverters begin to function as battery chargers for you HOUSE batteries.

The alternator voltage regulator should not see that charging voltage because the isolator prevents house voltage from flowing back. Since the voltage regulator battery sense circuit is detecting chassis battery condition the alternator continues to function and should continue to put out 28.4 volts.

So under what specific conditions does the voltage drop to 25, and is this house or chassis voltage?

The dash light fluctuation is an indicator the voltage is varying. As it goes up and down so does the light intensity. The fact that it is dash lighting tells me the variation at that point is with the chassis side of the system. Does the house lighting do the same?