Senya's sniper - Sniper Mask's sniper (duh)
The new Juo's sniper - Also Sniper Mask's sniper (I'll explain later using Mochizuki/Kawamura's Wakizashi)
Oribe's sledgehammer - Rika's sledgehammer
The Management Ninja Mask's knives - The Student Mask's knives
Asuka's metal rod - The Great Mask's metal rod
Yuri's guns - still just Yuri's guns lol
Nise - Nise lol
Mochizuki's Wakizashi - Yoshida's Wakazashi (technically in the prequel it says that the original Juo was going to use it before Possessed-by-the-administrator-Yoshida took it)
Kawamura's Wakizashi - It's said it's the same as Mochizuki, so possibly a duplicate of Yoshida's Wakizashi (A cop in the beginning of the prequel is shown with a katana, but I don't think it's his).
Interesting as Kawamura's is more powerful than Mochizuki's sword as Kawamura's "reeks of misery". So it's possible that the reason there's two of the exact same sword is to show one which represents Juo, or even Yoshida when he was possessed by the administrator, and the other is the real Yoshida, who saw himself as a failure, thus Kawamura's sword "reeking of misery". However, it's possible the same can be said that the administrator's sword is the one that "reeks of misery" as he was the first to be brought into the High-rise building realm in the prequel, and the misery could come from him never having the chance to become god despite being in the realm the longest.
That being said, as for the snipers, it's possible that they represent different states of Sniper Mask's mentality, one sniper being from when he was controlled by the mask, and the other(most likely Senya's) being from when Sniper Mask was fully aware of who he was(Yuka Makoto).