Look at www.freescale.com for the 11.09 BSP, it contains the LTIB tool for building uboot, kernel and rootfs. The Ubuntu rfs image should be on the site as well, so you can use that instead of the one built by LTIB. You can search this site for instructions on setting up an Ubuntu VM ( 10.04 ) to build the BSP and such inside, unless you are using a linux PC for that.
For your other questions I would search this site, USB cameras should not be difficult to get working with gstreamer pipelines, there should be examples here and as far as the wifi, there should be some experience on here for QSB + wifi. If not, you could probably try your wifi dongle and see if it works, if not, make sure the kernel driver is enabled/loaded, but for that you may need to do a customer LTIB build of at least the kernel? IF you try the dongle yourself and report back, someone here can help guide you, if it doesn't work.