Could you elaborate on what you trying to do:
1. Launch the standard Slack installation upon bootup?; or
2. Create a minimal Linux installation?
If it's the former, then if I understand your post correctly, your distro would impose its own partitioning and formatting decisions on anyone who installed it. Comment: for people already using Linux, they probably want to keep their existing partioning scheme, and if the installation process reformatted the entire drive, that would be an undesirable outcome. In the extreme.
If it's the latter, you might want to check out
http://www.damnsmalllinux.org/
Lastly, could this issue just be solved by not doing a Full installation of Slack in the first place? Given that Slack permits you to individually choose which packages get included, it seems unlikely that a person would end up with software they didn't want installed.
As I indicated there's a high probability that I don't understand your original post correctly -- J.W.