Speaker replacement 2001 Dakota

I very recently purchased a 2001 Dakota xcab with the Infinity sound system from the factory, or so I was told. Someone has replaced the speakers with Alpine SPR-17LS component (70 watts RMS) in the doors and SPR-17LP (50 watts RMS) in the rear panels. These speakers are still available for purchase so they have to be pretty new. The HU is the factory unit. I found, under the back seat, the Alpine crossovers still in plastic. I removed door panel to see if there were crossovers in the door, none to be found, I don't even know if there are supposed to be any. The situation is this, the tweets do not work with the exception of a crackle once in a while. The 2-ways in the rear panels sound like they are barely working. I pulled all of the panels and the speakers are wired, I am assuming correctly. The questions I have are this:

1. Does this vehicle have crossovers from the factory? If so, where would they be? If not, should the Alpine crossovers be installed because they are part of the component set?

2. Could the speakers be wired incorrectly or maybe the HU is going bad?

Any opinions or advise would be greatly appreciated.