Chronicles:
Eran Wiesel, within his discussion of the identity of the author of the commentary on Chronicles (הפירוש המיוחס לרש"י לספר דברי הימים, pp. 303-309), notes that though many Jewish sources over the years brought sections of this commentary in the name of Rashi, the author's identity has been disputed at least since the second edition of Mikraot Gedolot was printed in 1525, where it was referred to as the commentary "המיוחס לרש"י" (attributed to Rashi). And the Yaavetz wrote in his book Lechem Shamayim, Moed, p. 87:
"איך לא ראה או ידע את אשר כבר נודע לרבים שאותו פירוש. עם שהמדפיסים יחסוהו לרש"י ז"ל אינו כן ברם א' מתלמידי תלמידיו עשאו..."
Translation: "...how did he not see or know that which is already known to many that this commentary, though it was attributed by the printers to Rashi z"l is not so. However, one of his students' students made it..."
So by the Yaavetz's time, this fact was already known by many. The Chida also stated this in his book Shem Hagedolim, Maarachot Gedolim, letter Shin (the entry on Rashi).
Iyov:
On Rashi's commentary on Iyov, it's possible1 that the Chida wrote in the second part of Shem Hagedolim (שם הגדולים השלם, ועד לחכמים, part 1, p. 116):
"ובסדר הדורות ריש דף קע"ז כתב דבפירוש איוב דבידינו מזכיר לרש"י וא"כ גם פי' איוב אינו לרש"י."
Translation: "And in Seder Hadorot p. 177 he wrote that in the commentary on Iyov that we have he mentions Rashi and therefore also the commentary on Iyov was not written by Rashi."
However, it seems that Rashi did write most of the commentary on Iyov, until chapter 40. Jordan Penkower, in his essay on the end of Rashi's commentary on Iyov, points out that 12th century scribes all knew that Rashi's commentary ended on chapter 40, and at some point, other commentaries were added, most notably that of Rabbi Yaakov Nazir.
Ezra and Nechemiah:
Wiesel, in a lengthy essay on the commentary on Ezra and Nechemiah, notes that the first person to doubt Rashi's authorship of the commentary was the Reform maskil Avraham Geiger, so from that aspect, it's not an Orthodox position. However, he also analyzed many medieval commentaries and showed that ideas from the commentary were referenced by other authors but not attributed to Rashi. That means that those commentators were aware that the commentary was not by Rashi.
Megillot:
As for Ruth, Song of Songs and Kohelet, I think this is the first time I'm hearing the claim that they were not authored by Rashi. I was not able to find any academic evidence on this, and as this comment in Wikipedia is unsourced - it seems baseless at this point.
1 I was not able to find it in the first edition of Shem Hagedolim, which was printed in two parts in separate years. Shem Hagedolim in its original form was not very organized. Rashi's commentaries and attributed commentaries are referred to at least twice, once in the first part (maarechet gedolim) and once in the second part (maarechet sefarim). The second reference expands greatly on the subject of the attributed commentaries but does not appear to mention Iyov. It does, however, refer to p. 177 in Seder Hadorot (ed. 1769), which mentions both the commentary on Iyov and on Chronicles as referencing Rashi explicitly. Shem Hagedolim was reprinted in a revised edition in 1864 by Yitzchak Ben-Yaakov who stated that other than restructuring the book (such as grouping together all the information on the attributed commentaries under a single entry), he made very minor edits into the Chida's wording, just so the text would be smoother to read. That being the case, I do not know if the commentary on Iyov is simply mentioned in a third location in the original edition and then grouped with the rest of the quotes, or if its mention was added in by Ben-Yaakov.
