A brushed motor would only need two wires. A brushless sensorless motor can get by with the three phase wires. It might contain a speed sensor, which adds three thin wires. As you probably know, your typical ebike motor is brushless with Hall sensors, which means three heavier phase wires, five wires for the hall sensor, and sometimes a ninth wire for an internal speed sensor. It's likely that bike uses a brushless sensorless motor, but if you already have a working controller, just stick with it. Nothing but trouble happens if you stick a bigger controller into a front drive bike,
That bike probably takes a 36V silverfish battery, They slide down the rail in front of the rear wheel and a locking pin from the battery case uses the hole at the top of the rail. Should be two vertical pins in a plastic plate at the base of the frame for power. When you buy a silverfish battery, a decent seller will include a new rail, a new base plate, plus terminal pins for the plate, You should always verify that the new battery has the pos/negative pins aligned the same as the bike. It's easy enough to switch either side to match.
