In case anyone was curious, this was solved in two basic steps. I wrote a simple shell script to add our nameservers to the resolv.conf and in turn execute it
by using the Packer shell provisioner. The second set was to use the Packer shell provisioner, again, to execute a bunch of one-liners using the "inline": parameter
to move the existing repos to the "yum.repos.dislabled" directory and then use wget to download and load our mirror. This allowed me to install Ansible successfully.
"sudo wget https://repo.<your_business>.com/download/<your_mirror>.repo",
"sudo yum clean all",
"sudo yum repolist",
"sudo yum install -y ansible"