I crossed two wires, and fried my circuit. How do I test for parts that need replacing? (I'm new to this, schematic included)
Probably you fried only the transistor and maybe the mosfet. The speaker is probably good. you can disconnect both the transistor and the mosfet or eventually speaker and coil and measure with an ohmmeter the resistance between drain and source or collector emitter. if you find a short, the part is broken.