Hm, I don’t think it is related to your subsequent problem, but it seems the BusyBox head command has dropped support for the traditional head -<number> invocation to save a few bytes on the executable size - at least I believe installing on a BusyBox system has worked without problems in the past. Perhaps the ConfD installer should be changed to use the POSIX-standard head -n <number> invocation. If you’re brave:-), you could try modifying the installer (the initial part is a shell script) with sed 's/head -1/head -n 1/'…
This indicates that the errors from the installer aren’t actual problems - those invocations of head are just part of the logic to report missing libraries, and if you actually had some missing libraries, you would probably not be able to start ConfD, far less make an ssh connection get as far as a rejected authentication.
The initial install does not include a local user called root (only admin and oper) - did you create it? Or do you expect ConfD to use PAM for authentication of root? PAM is enabled in the sample confd.conf, but it typically requires a bit more setup, see the User Guide. Additionally many Linux distros are set up with an “invalid” password for root, expecting you to use sudo instead of logging in as root or using su. In any case, check the audit log, it may have more information on the reason for the failed authentication.