hereorthere! Yehoshua finished the Torah?! Chas Veshalom!
The Halacha is that you are not allowed to be Mafsik by the last eight Pesukim so that it should not appear that these Pesukim are different than the rest or written separately. The Gemara says that Moshe wrote these Pesukim with tears.
As far as if he learned our Gemara, it says that he learned every question that a studious Talmud would ask his Rebbe