I was thinking of adding the dates from the final Timeranger episode, Super Sentai Compilation, to the time conundrum thing you're working on; but I also do wonder if that would count as continuity or not before adding them. (though it would confirm stuff like "Ohranger actually happened in 1995, not 1999)
Like Doctor Who, I try to avoid using the word non-canon with this franchise due to its lack of a concrete policy ala Star Trek/Wars. But... I mean, there is no fourth wall here. And the cast, while in-character, say that their TV show is ending.
Nevertheless, this special episode will be acknowledged on the page, while making its status clear.
Well, the Ridewatches are a prominent part of Zi-O's story, while the Compilation is non-canon. Honestly, this page isn't really about a "solid" timeline, which you could never really have 100% consistent. As stated in its introduction, its more a compare and contrast trying to make sense of it all, inspired by the UNIT dating controversy, which addresses conflicting dates for various Doctor Who stories.
Basically, we've got the order of history/events, then the "dating conundrum" page focuses on the logic issues behind it. For instance, Gokaiger would seem to be set in 2011 from the point of view of its successor, but perhaps not from its predecessors. I mean, the gap between Brajira's defeat and the Gokaigers' arrival on Earth would clearly be a LOT more than a single week in-universe.
Of course, in the case of Ohranger, everything points to it beginning in 1995, within the "VS World", as opposed to 1999 in-show.
Super Sentai Compilation, a special episode of Mirai Sentai Timeranger following the finale, acknowledges the first 25 Super Sentai according to their premiere year as the Timerangers travel through time to observe their predecessors and immediate successors. However, it is noted that the Timerangers introduce themselves to the viewer as commemorating the conclusion of their TV series; as such, the special is not within the series' continuity.
J.A.K.Q. Dengekitai (1977) is acknowledged as the Super Sentai of 1977 by Super Sentai Compilation.