I see several problems here.
First of which is you bought a third party display assembly and installed that. I could give a gerbil's rear whether or not some website claims it will work with your specific model system, having had years of experience repairing Apple systems, I can tell you that they are VERY finely tuned. Maybe a little too much so, but that's not something we have any control over. The power conduits on the MLB are designed specifically to provide just enough power for the maximum CTO options for the unit, nothing more.
Moving along, checking with the service manual for the Early 09 17" MBP, the airport card is located under the display clutch cover, and that means that the webcam/airport data cable should be a single part of the display assembly itself and not something you can just replace. So that makes me wonder if maybe you're misidentifying your particular model or if this "upgraded" display assembly is not just some dumpster dived display of questionable quality, but a completely third party product. If that's the case, there's no telling whether or not the airport card will work with that particular cable. I also know that with the "official" Apple parts, you have to be very careful to get those cables in the right way. They have special grounding points on one side, which your display may be lacking, and is allowing a lot of interference into the signal stream.
Then I don't see any details about how you went about doing the repair. While it's rare, if you don't disconnect the battery while messing with the LVDS or data cable, it's possible to send a surge up the line. As long as the battery is connected, and has a charge, there is live current running through the MLB. You could damage the display assy, the airport card which is in the display assy, and even cause a feedback loop damaging the MLB.
The fact that the keyboard backlight doesn't work anymore might suggest that this new display is trying to draw too much power, and even though the keyboard backlight doesn't need much, the display is taking just enough. Or, while trying to install the display assy, you pulled the MLB even though you didn't need to, and then didn't reconnect the flex cable for the keyboard backlight.
Now that we have all the facts out of the way, the part about how the unit appears to function more or less correctly without the airport card points the finger pretty squarely at either this "upgraded" display being a complete POS, or that you've damaged the MLB.
If you put back the original display panel, does the problem go away? If yes, your display is the problem, and if no then you probably damaged the MLB and you'll be lucky if all you damaged was the data port for the display assy.
<div>I'm hoping someone here can help me out with my sick Macbook Pro. I have an early 2009, 17" MBP with the 2.66 GHz Core2Duo processor, 4GB ram.