Arduino Compatibility

Hi there,

I bought an Arduino Uno, well over a year ago. I bought a starter kit with it (from Oomlout; see here), but never made anything much more advanced than the samples that came with it. I am a programmer, so that side is no problem, but now I want to try my hand at making something cool with it.

I have a Cybot, that's three quarters complete, lying around, so my first thought was to try to get this to working with the Arduino, but after many days of trying to get it working, and especially since I have no previous experience with electronics, I had exhausted any help from IRC, etc.

Now I plan I buying a few extra things to try and get a moving platform with some sensors on board. Oh, and the Uno is an R2.

to simplify using motors: Arduino Motor Shield R3, (I have some small DC motors, they are roughly the same size; how do I even tell what um... spec? are they? Would you recommend getting a set of new ones to guarantee compatibility?) (Also, is this R3 board even compatible with the R2 Uno?)

so it can see: UHC-SR04 Ultrasound Sensor,

I wanted some sort of remote control over it, for which I was thinking of using Wifi: SainSmart Xbee Shield Module for Arduino UNO MEGA Duemilanove, with XBee 1mW Wire Antenna, (Would these even be suitable?)

I have a lcd display too, which I would probably add for live debug information.

Ideally I would like some sort of camera to go with it, but I think that might be step too far for now.

So, is this feasible, at all? I presume the motors at least would need an independent power supply, and possible some of the others.