Can you replace a fuel pump through the back seat of an 96 s10 ls chevy blazer?

No, you generally cannot replace a fuel pump in a 1996 Chevy S10 Blazer through the back seat. While access to the fuel pump might be *somewhat* improved by dropping the rear seat, the fuel pump is located in the fuel tank, which requires dropping the tank itself. This usually involves working from underneath the vehicle. There isn't enough room to access and safely manipulate the necessary components through the back seat area.