Im going to try not to be an booty here, but all of your questions are on the internet. The 08-12 kk (liberty) are the same wire harness including the limited and jet models. Most of installs on the audio are plug and play but require some reasearch

and common sense.
Pairing the stock and alpine amps is a STUPID idea. Your not going to benifit whats so ever with them. Just a headache.
If this seems to confusing of a task, save your time and let a profesional do it.
Also, asking another fourm like alpine or others like them what to do. This is no task for a beginer for sure.