Okay, if I'm taking this the right way, we (very simply) think about it this way, sp hybridised as a triple bond (i.e multiple bond to the other heteroatom in the case of nitrogen, carbon is a triple bond and a single bond to a hydrogen). sp2 hydridised is a multiple bond and single bonds, and sp3 hybridised is single bonds.
I realise that makes little sense tbh.
So yes, N2 is sp hybridised, and is linear.
N2H2 (which I'm pretty sure doesn't exist, tbh) has a double bond between the nitrogen atoms, and a single bond to each hydrogen, making is sp2, I think. I'm pretty sure it would not be linear, because the lone pairs lie "next" to one another rather than opposite one another.
N2H4 has just single bonds, making it sp3 hybridised.
I always think about it more about the bonds, rather than the shape of the molecule. But then again we've only talked about hybridisation in relation to carbon.