NO, once you have soldered your LISY PCB it is a 1:1 replacement as all the original connectors do fit with LISY. So just grab your original board and replace it with LISY, this can be done i a minute
LISY does not only replace the original MPU by 100%, it also provides you additional Features such as a web based test (LISY_control), optional Soundboard, Freeplay Option and no need to use batteries any more. For a full list of Features have a look into the user guide
Use the Gerber data provided and order the PCB at shop of your choice (see instructions for ordering at 'jlcpcb.com' at section 'PCB')
No, you need to solder yourself or find someone who can do it for you. However soldering a LISY PCB is not difficult, just give it a try. Even for unexperienced People it can be done in less than three hours.
LISY does use the original soundboard of your pinball machine. As an add on you can use a soundcard and use your own mp3/wav files. Have a look into the user guide how to do that