I have just purchased a 2018 Equinox and find the discussion interesting. The "Owners Manual" certainly isn't real clear, but the GM bulletins and forums have been very helpful. The selling Dealer could only tell me only the 1.5L gas FWD is towable and that's what I have. My 2012 Chevy Silverado that I traded was a dream to tow. Instructions were easy to follow and it traveled many miles behind our Journey.
Apparently you have a gas generator. However, if it's a diesel, AMSOIL has a 15W-40 that I use in my generator and it meets the requirements of Onan. It provides 4 times the protection required by Onan and is designed for extended oil changes.