I disagree. The main villain in Ganbare Goemon 2 is General McGuinness who is an obvious Hulk Hogan parody trying to take over Japan. The whole theme of the game's story is making fun of foreigners trying to meddle in Japan's affairs, so for that reason, I think Goemon would have a slight folksy xenophobic bent, but don't get me wrong here, I'm not saying that's terrible and he should change, I'm more of the mindset that this is an interesting character flaw of his. It could be something to explore, and with Smash I'm all about exploring all the myriad character interactions that could happen and trying to pick the most interesting ones. I'd write it in a way that undermines it and he learns to grow out of it. It's not supposed to be a big deal, it's just that's the way the character is portrayed. I think characters are more interesting when they have flaws.
That's the whole point. Goemon calling him "aniki" is supposed to be ironic, because it's supposed to boost his courage. Goemon's sense of justice, from what I've played in the games, is always about standing up for people who can't stand up for themselves, offering a helping hand to those who need it. This is a theme they tackle multiple times in the N64 games. I think Lucas would make a good counterpart simply because he is timid and kind of cowardly, as opposed to Goemon's courageous and hot-blooded nature. If Goemon's just paired up with characters who share his courage then there's no real interactive character dynamic since they're all motivated and agreed on the same thing.