I just did a research, and I haven't been able to find information from the studio that created Inuyasha, Sunrise, or the original network that first aired it, Yomiuri TV, concerning more than one season. In fact, only by looking at the episodes original release dates one can notice there were no official periods without episodes from episode 1 all the way to the last episode (167) of the first series, and different seasons were never mentioned during this airing.

Besides, Inuyasha: The Final Act should be considered a whole different show, even though it retakes the story from where Inuyasha left it.

On both points, both AniDB and MyAnimeList agree with me. IMDB just took the season frame from the later released DVDs, and shouldn't be considered right, since in TMDB "episodes should be added exactly as they first aired on the original network". Viz Media also has this season frame, but, even though they have distribution licence, it should be considered an international release, and, therefore, "should not be used as templates for anime".

I'd start just adding the rest of the episodes to Season 1, but episodes are locked for season 1 (at least). Please, unlock it.

Thanks in advance 😊