All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
It is valid to perform the Friday prayer in the mentioned places when there is no more room in the mosque, but the Tahiyyat-ul-Masjid prayer is not required in this case. Before the Khutbah starts, it is permissible to perform any voluntary prayer in such places, but not the Tahiyyat-ul-Masjid prayer. When the Khutbah has already started, the majority of jurists hold the opinion that one must sit and listen. Maaliki scholars even state that it is impermissible for one to start any prayer, whether Tahiyyat-ul-Masjid or any other prayer, when entering the mosque during the Khutbah. So what about those outside who shouldn't even pray it in the first place! They argued that one must listen instead. The Maaliki scholar Ad-Dusooqi said:
"The preponderant opinion is that it is prohibited to speak during the Khutbah at all, whether one is inside or outside the mosque in the roads connected to it. It is also applicable whether one listens to the Khutbah or not." Ibn ‘Arafah said: "Most scholars have the opinion that silence during the Khutbah is also due on the one who does not listen to the Khutbah, even if he is outside the mosque."
Allah Knows best.