wannabe,
Go to sonicelectronix.com and search the Kenwood KDC-MP638U head unit. At $130, this is the cheapest Kenwood HU they carry that is compatible with the factory remotes. The key is the light blue wire comimg out of the back of the chassis as seen in the pic below. It is labeled "Remo Cont" (hard to see in this pic but it's easy to see on the pics of the other more expensive Kenwoods) and this is the wire that you need to connect the remotes to. If it doesn't have this wire, then it's not compatible with the factory remotes.
I bought a similar model (Kenwood eXcelon KDC-X692) that is now discontinued. I would personally go with the Kenwood KDC-MP442U for $10 more as it has aux and USB inputs on the front. Like the KDC-MP638U, it also has 3 pairs of 4V preouts which is important if you decide to add amps down the road.
As far as wiring your 6 speakers to the 4 channels on the head unit, just do what the factory does - wire the 4 rear speakers in parallel to the rear channel and wire the front speakers to the front channel.
Also, I don't see why your white Aeware remotes wouldn't work - I haven't heard of any of them going bad.
Good luck with the project.
Al
http://images.sonicelectronix.com/im.../kdcmp638u.jpg