My first thought is that if you are running two air conditioners you are going to need many times greater than 2,000 watt hours of capacity unless you will be running the gas generator when running the AC.
Yes to all questions. We are doing all but DC-DC charging. Not worth it with 1750W of solar on the roof.
In a nutshell, we connected the RV Plug input to the AC300 input and then the AC300 30A output to the RV mains and the 12V out put to the RV 12V. Basically the RV is always running off the AC300. Shore power and solar charge. When we rarely use the generator, we just plug in via the RV shore power connection.
We also have a way to bypass the AC300 and run just from shore power.