Ashru785,
The external device (firewall) will need to forward 443 request to ADFS not exchange in order to get that to work. Additionally, having one ADFS servers is not a recommended deployment given that if it its unavailable users cant login to O365.
Short answer, no, you will need two external addresses.
All of that being said it based on my experience and deployments. I did conduct some google fu and found this article explaining how to change the listening ports.
http://www.inogic.com/blog/2014/07/how-to-change-the-port-of-adfs-3-0-windows-server-2012-r2-to-444/
I stand by my earlier comment, you should have more than one ADFS server, I recommend a full 4 server solution as outlined by Shane Jackson.
https://gallery.technet.microsoft.com/office365/ADFS-Design-Considerations-f30c0b95
Good luck,
JP