What are the 8 wires on this rechargeable lithium-ion battery?
From the color code of the wires it's obvious that you have 3x B- and 3x B+ on the sides. The schematic in the datasheet suggests that the two wires in the middle are P- and NTC, for temperature sensing.



I don't speak any Chinese, so you can only trust my statement that much.

Regarding replacement batteries, if your system has only two wires, it's more or less safe to take a battery with extra connections (like temperature sensors) and simply ignore them. However, if your system expects a battery with temperature sensing, connecting a battery with only two wires is not recommended, and may be impossible: many systems won't charge a battery if they don't get a reasonable signal on the sensing inputs.