I stumbled upon a free alternative to DVDFab for ripping DVD-A to ISO. Not easier, but an alternative.
Use Foobar2000 with the dvdadecoder software component installed, and open the AUDIO_TS.IFO file in your optical disc's AUDIO_TS folder. Foobar will populate with the various MLP MCH and Stereo tracks. Right click on any of them, select "File Operations / Copy To...". By default mine came up with "File name pattern" of %filename%. If it doesn't, put that string in the box. Check "Copy entire source folder content". Then click on the "..." in the "Destination folder:" box, and choose a folder on your hard drive. Click "Run", and after a few minutes the various .AOB files and all of the other files in AUDIO_TS will be decrypted and copied.
Next, use your favorite tool for decrypting and copying VIDEO_TS folders from DVDs (not for extracting/recoding the video, but for copying the various .VOB and other files under VIDEO_TS/). The very old original DVD Decrypter works fine, and it still works in Windows 10.
Once you have your separate decrypted and copied VIDEO_TS and AUDIO_TS folders, put them inside a new folder. Then use Imgburn to create an ISO from the top level folder contents. Imgburn will notice a non-empty AUDIO_TS folder and will advise you on creating a DVD-A ISO.
I just tried this with one of the Talking Heads dual discs (DVD side obviously), and my jail-broken Oppo happily played it as both DVD-A and DVD-V. I'm hoping to use this technique to rescue a DVD-A that DVDFab won't copy because of corrupt sectors, but which plays correctly in my Oppo. Those corrupt sectors might be an accident or perhaps they were put there on purpose.