Hybrid conversion

Hello, me and my dad are looking into converting our ford taunus transit from 1963 into an ev, but we are wondering if an hybrid would be possible as it would let us start out with less batteries and use the engine if we would run out of range. We originally were looking into hub motor but there is not much on the market.
I thought it might be possible to install a 4*4 transfer case and mount an electric motor too the output that would originally be for a drive shaft to the front wheels, this way when driving with the electric motor we could put the transfer case in ''4wd'' and put the transmission in neutral, and we should still be able to use the ice when in ''2wd''.We are not looking for a fast car we would be more than happy with a top speed of 80-90kmh.
However I don't know if you can input power on the output side of the transfer case and if we could find an appropriate motor.
Any ideas and comment would be greatly appreciated.