I'm getting closer; making a link is good; but my node rpc listens on my local IPv4 address and not on localhost. so I think that is why it still is complaining about not finding bitcoin-cli. Does c-lighting have a config setting for host user and password?
I don't use C-Lightning, but have you check out this documentation here?
https://lightning.readthedocs.io/lightningd-config.5.html