You can install GNU coreutils out of the package repo no problem. Software packages are mostly available except closed source stuff that is Linux-only at which point you would use the Linux compat layer and it mostly works.

Docker is Linux-only for now but there is movement in that area. BSD had jails first and there is work on making generic containers work across multiple operating systems, including BSD. But I think the point of using BSD is to not bring Linux with you. Try their way and see how you like it.