When Did R. Dosa Ben Hyrkanus Live?

The Rambam writes in the introduction to his commentary on the Mishnah (Kafah edition, p. 28) that R. Dosa ben Hyrkanus lived at the time of Shimon Ha-Tzadik and had such a long life that he lived into the time of R. Akiva. In other words, R. Dosa ben Hyrkanus lived for over 400 years. Unsurprisingly, the Rambam's student R. Yosef Ibn Aknin writes similarly in his Mevo Ha-Talmud 10:1. R. Yitzhak Abrabanel (introduction to Nahalas Avos) also follows this understanding.

The Rambam's source seems to be the Yerushalmi Yevamos (end of ch. 1) that R. Dosa ben Hyrkanus said that R. Elazar ben Azariah looks like his ancestor Shimon Ha-Tzadik. Alternately, his source might be Yevamos 16a that R. Dosa ben Hyrkanus testified that the prophets Hagai, Zechariah and Malachi had sat on a certain stool. Both passages imply that R. Dosa ben Hyrkanus was alive at the time of Shimon Ha-Tzadik and the last prophets, and the time of R. Elazar ben Azariah.

However, that anyone would live for over four hundred years seems quite amazing.

The Meiri (introduction to Avos, published as Seder Ha-Kabbalah pp. 50-51) explicitly argues on the Rambam and suggests that R. Dosa ben Hyrkanus merely had traditions about the ancients and was not an actual witness to their lives. I saw that R. Sherira Gaon is also quoted as implicitly disagreeing with the Rambam (I believe from Sha'arei Teshuvah no. 187). The Rashbatz, in Magen Avos 1:1 (sv. u-nevi'im), says that R. Dosa ben Hyrkanus lived after the destruction of the Second Temple and that Hagai must have lived very long if R. Dosa ben Hyrkanus saw him.

R. Aharon Hyman (Toledos Tanna'im Va-Amora'im, pp. 322-323) suggests that because R. Dosa ben Hyrkanus was rich, as we know, he might have owned an antique with Ezra's image, perhaps also a stool on which prophets had sat.

The Seder Ha-Doros asks on the Rambam from Gittin 81a that Beis Shammai was doros ha-rishonim (the earlier generations) and R. Dosa ben Hyrkanus was doros ha-aharonim (the later generations). This certainly implies that R. Dosa ben Hyrkanus was not from the very first generation of the Second Commonwealth. The Hida, in his Pesah Enayim (ad loc.), answers that perhaps R. Dosa ben Hyrkanus was not ordained until late in his life and is therefore called doros ha-aharonim.