dual wireless arduinos which flavor?

greetings :) 2 part question

project scope = 2 arduinos (1 uno which i own) and 2 xbees. the question is would i be limiting my funfactor by purchasing a 2nd uno? or should i go with a different model? im not real clear on the differences, or if there is any big differences other than pin(s) offered. im probably going to have sensor information flowing between the 2, maybe some motor/servo control. maybe even a remote to control a little vehicle to chase my dogs around. i dont want to buy remote controlled vehicle im retired and im bored and i want to build all the stuff. not looking for code, just really great/fun way of using all this stuff together to maximize stimulation to my lil brain.

part 2. ive got my eye on these https://www.sparkfun.com/products/8742, so the interface between these xbees and the arduinos would be? would also like to dual use that interface to configure said xbees via usb, and/or use one connected to laptop, plus arduino to arduino. xbee explorer the answer? or cheaper way? i can solder well, would these be part of my solution? https://www.sparkfun.com/products/8276

thx in advance, you know reading about the products for hours tends to blur and confuse, especially since i dont have the parts in hand to mess with. i welcome some advice, insight, even what your favorite way of doing this is. thanks much.

My suggestion would be to start off with a couple of UNOs and a motor shield. Almost every type of shield is compatible with the UNO and this is a very flexible platform. You can get variants with more pins, or smaller ones, or ones with extra devices onboard, and you always have the option of scaling up or down later if you feel inclined, but the UNO is a very solid starting point.