I like the suggestions for the Chinese UP and UB names.
Whether the UP would be actually useful depends on its actual effect, of course, but I'd like to have it make China at least be on par with Europe when those civs spawn in combination with the UU. That should suffice to get at least some effect out of it while you're competing with them, but allows them to overtake you until they're in the Renaissance (the early Renaissance was roughly the technological break-even point).
Now on to Japan: as Linkman already said, it's Rhye's and Fall of Civilization, not Rhye's and Fall of Polities, and the Japanese civilization did exist before the Edo period (with a rather strong Tenno for its time in its early centuries, even), so a spawn in the 1500s doesn't really make sense in my opinion.
I also don't want all Japanese goals to be about post-Meiji Japan, so there's got to be something that represents Edo Japan or earlier. I agree that while the generals goal fits historically, the necessary ingame behavior doesn't really, and I also agree that "don't open borders with anyone and insult everyone who wants to trade resources with you [i.e. act like the Tokugawa AI on a bad day]" doesn't really make a good goal. So you're right that this probably only leaves us with an "acquire X culture in ~1600 AD". I tried to avoid something like that because it's a stupid builderfest, but it's probably the only option.
The only other alternative I could think of (although admittedly it's more Hollywood history than anything) is something espionage related as in RFCA, like "Steal X techs by ~1600 AD". We could also interpret that as adapting Chinese technology into Japan which happened fairly often in early Japan.
I still like the great general goal, maybe it's appropriate for Prussia later on (representing Prussian military theory like Blücher's or the Generalstab in general).
On the historical discussion: it's true that isolationist Japan is an exaggeration that's especially widespread in the Civ4 community due to how Firaxis portrayed them. And Perry's aims with Japan really didn't amount to vassalization. It was just standard gunboat diplomacy to get them to open borders. Oh, I forgot, gunboat diplomacy was only for those evil imperialist Europeans
