How do we properly add a PTR record under the DNS zone for WHM? By adding a PTR record will this show our domain name vs our hosting company domain name upon running a rDNS check?
It's unlikely you'll be able to add a PTR record yourself. You'll probably need to ask your host to do it for you. Just tell them what you want the PTR record to say for the IP address (assuming the IP address is for your exclusive use).