Congratulations on fostering and your future adoption. We have recently adopted a pair of feral cats who will live in our big RV garage. The Feral and Barn Cat Rescue organization has a whole protocol on how to adapt feral barn cats to your barn, so that they will continue living there. We will supply food and shelter and they will keep our area clear of rodents.
Regarding the background material I used for Anabelle. I bought it on eBay. It comes in several colors. The first I purchased was dark blue (since most of our dogs are primarily white).
I paid about ten dollars for the material.
http://www.ebay.com/itm/121605398168...%3AMEBIDX%3AIT'
We liked it so much that I purchased an additional teal and purple colors.
I normally use fleece as I did in these portraits of Anabelle.
I have fleece in a multitude of colors. The way I use the background material is to place it over an armchair. I light the portraits with an on-camera hotshoe flash bounced off the ceiling and modified with a Joe Demb Flash Diffuser Pro. I often use a 4 CFL bulb softbox and a OTT hobby light as fill and background lights. I don't seem to have any problems with mixing the light sources. I use a WhiBal target.