Are the prayers performed by the questioner outside the mosque or by combining prayers considered a barrier to attaining the virtue of the Hadith: "Whoever prays to Allah for forty days in congregation, catching the first Takbir, will be granted two immunities: immunity from Hellfire and immunity from hypocrisy"?

The gist of all that the questioner mentioned is that he prayed his prayers in congregation outside the mosque. If this is what is meant, then the questioner attains the virtue mentioned in the hadith (definition), for the mosque is not a condition for earning the reward of congregational prayer. Rather, praying in congregation is sufficient, whether inside the mosque or elsewhere. Mulla Ali al-Qari said: "In congregation, meaning with a group, even if it is one person, in a mosque or elsewhere, he is granted immunity, meaning purification from hypocrisy."