I just tried rbf for rpi2 with redsleeve. It worked quite easy form me. I have one remark: maybe it's a good idea to cleanup all rbf related yum repofiles after package install. I now end up with a couple of double repo's and also a couple that don't work in the image, as they were local to the machine that generated the image.
You make a good point but removing the very repositories used to create the image will create a problem in the present CentOS image. You'll be left with no functional repositories.