About the CSS problem, it should be fixed with my latest commit on github (you can try it if you want).
About the metadata update, I don't have the same problem on my Nas, it's working fine. Have you tried many epubs ? If only some cause problem, can you send me one epub so that I can test myself.
I don't know IIS a lot but I guess the firewall exception should be automatic. Or you can try to add the TCP port 80 ou 443 if you're using HTTPS ....