Hi Mikhail,
We actually did something very similar in Sacramento, they also allow two ADUs. For us, every time we ran the numbers the "triplex" just made more sense, plus the layout just screamed triplex. When you have to do so much work, whether its 1 or 2 ADUs, the better compounding returns was always 2 ADUs. The tricky part we had was the refinancing, I'm not sure where the F&F rules are at with 2 ADUs now but we did manage to get ours refinanced, almost a full BRRR, and appraiser treated it as a triplex. We called it a triplex to lenders and a house with 2 ADUs to the City when they were looking for impact fees and utility fees!
Couple of things to watch out for, 2 attached dwellings are considered Residential for Building Code purposes. Once you go to 3 attached dwellings or more, there's a good chance they will make you treat it as a "Commercial" project for Building Permit approval. That means a change of use and, for us, meant sprinklers and making one unit ADA adaptable. Returns were still very much worth it but 2 attached units + 1 detached is potentially more economical. And if it "looks" like a triplex, all the better for refinancing too!
Hope that helps!!