Your generator may need a plug adaptor (mine did)
https://www.amazon.com/Camco-55333-3.../dp/B0011FLODA
This will allow you to plug directly from the Passport to the 30 amp outlet on the generator. I can't tell for sure if the Ryobi is equipped with a 30 amp outlet but if not the standard 120v to RV 30 amp "dog bone" adaptor is all you'd need.
You should wire the two batteries together for maximum amp hour storage and ease of charging. Your converter will charge both with no problem.
At 15 amps the Ryobi may not start your A/C but it will run the rest of your 110v accessories.
We would run our generator for 1 to 2 hours each day to keep our batteries topped off. You don't want lead acid batteries to drop below 50% discharge.
We've gone over a week on batteries dry camping using the above process. The limiting factor being the black water tank