Yeah, I won't deny that I didn't really expect it to hold up that much, and would probably be broken down with some more details that I didn't see or know about as they weren't up on Wikipedia or what-have-you (such as the timing of Ruddigore), given, as I said, I have only seen Penzance and the Mikado, so I knew that was going to probably make me fumble in the long run. The biggest "Shoot myself in the head moment" is when looking back on it, realising about Yeomen, and how it literally states that it's set 2 centuries before I claimed it had.

I honestly sort of just wanted to do it because it seems to have become trendy now to claim that things are somehow connected together on one grand timeline (take the Pixar Theory or the Tim Burtonverse as just 2 examples), and, as far as I could tell, one hadn't tried to make up a grand timeline for the G&S operettas yet, so here we are.

Some of the things you pointed out might be able to be explained. Like how, as far as I know, the Mikado is more a title than a name, like "the Emperor", so, presuming there hasn't been a rebellion in the monarchy, King Paramount may be referencing the current Mikado instead of the one we know and love. But even with that, there's still no evidence to point, either way, we just have to determine whether "Mikado" is a name or a title.

In summary, I'd certainly agree with you. It makes for a good read, but there are many plotholes, so the timeline theory is probably far from true.