What is the number of unpaired electrons of nickel observed in $[Ni(CN)_4]^{-2}$?

The hybridisation and geometry of $[Ni(CN)_4]^{2-}$ are:

The hybridisation of $Ni$ centre in $[Ni(PPh_3)_2Cl_2]$ and $[NiCl_4]^{2-}$,respectively are

The shape of $MnO_4^-$ ion and the hybridisation of $Mn$ in $MnO_4^-$ is

The ammine complexes of metal ions $Cu^{2+}$,$Ni^{2+}$ and $Zn^{2+}$ have shapes respectively:

$A$ coordination compound is made of $Co^{3+}$,$NH_3$,and $Cl^{-}$. $A$ $0.1 \ M$ solution of this complex when treated with excess silver nitrate gave no precipitate. The formula of the complex and secondary valency of metal are respectively.