/etc/hosts.equiv -- at least tell it about the machine from which Arusha-oid rsh's will come from. (Not necessary if you [wisely] don't touch rsh with a bargepole.)

/.rhosts -- if root is (temporarily?) going to need to come in from some other machine, record that in here. (Ditto about the bargepole.)

HP-UX only: /etc/rc.config.d/nfsconf -- at the very least, change to use the new automounter, AUTOFS=1.

HP-UX only: /etc/csh.login -- you may want to toast/modify this, depending on how you're setting up users' environments.

/etc/exports -- if you want to make some of the new machine's disks available (temporarily?) for other hosts to write on (e.g. so they can scribble some initial ARK stuff into place...), then edit that in here, and then do exportfs -a. (Solaris only: it's /etc/dfs/dfstab, and a different syntax. But you knew that.)

/etc/passwd and /etc/group -- initial versions, perhaps from a similar already-going box.

/etc/auto_* (automount maps) -- initial versions, perhaps from a similar already-going box.