i think in either iasip or seinfeld, charlie could pull elaine. however, i think it would be a one-off goof and not a relationship of any duration. we've seen that elaine has not the best taste in men and has dated some fairly weird guys throughout the show. on the other hand, while puddy and charlie have a similar vibe in some ways, as someone pointed out, charlie is definitely way odder than puddy and exists outside of societal norms. however, charlie is sometimes able to date attractive women, i.e. ruby. it's also worth considering the episode where elaine briefly dates a homeless married man before figuring out what's going on. with all this in mind, i posit that charlie could briefly attract elaine's romantic attention via a series of elaborate scenarios that accidentally conceal how weird he is, and the charade would fall apart by the end of the episode.