Ezekiel (Yechezkel) 40 begins a section about a vision of a temple with priests and sacrifices and feasts. The detailed descriptions of this temple seem to indicate that a literal (as opposed to figurative) temple is being described. Should it be identified with the one built after the Babylonian captivity? And if not, when and under what circumstances will it be built?
I understand the Rambam below is referring to your chapter (so no it is referring to the one not yet built (it shloud be speedily rebuilt)
The [design of the] structure built by [King] Solomon is described explicitly in [the Book of] Kings. [In contrast, the design of] the Messianic Temple, though mentioned in [the Book of] Ezekiel, is not explicit or explained. Thus, the people [in the time] of Ezra built the Second Temple according to the structure of Solomon, [including] certain aspects which are explicitly stated in Ezekiel
Regarding what we are waiting for
Also See answer https://judaism.stackexchange.com/a/28700/5120 even though in the comments some one argues I still understand that we are waiting to tip the scale
We pray every weekday at least 3 times a day for G-d almighty to bring him
Re who will build it see Will the mesiah build the 3rd temple?
Rabbi Yehuda Shurpin in these two articles states that the Second Temple was not modeled after Ezekiel's temple (reason given) and that only in the Messianic age will it be built exactly as he described it.