Hi Raam,
To add a managed server, you do the things documented in "Managing Configuration of Oracle HTTP Server and Web Application Services in Oracle E-Business Suite Release 12.2 (Doc ID 1905593.1)" -> 4.4.1 Adding a new managed server . Nothing more..
It seems you already did this.
Let's answer your questions;
1) You give the port number while running adProvisionEBS.pl.
This is from my book:
http://www.apress.com/br/book/9781484214237"The Managed Server port should be chosen in a way that it does not conflict with the listener ports of
other Managed Servers running in both the run environment and the patch environment. That is, if you
have your oacore_server1 listening on 7201, it means it will listen on 7202 after you make the cutover.
So if you have oacora server 1 for oacore1 listening on 7201 , then you should think that it will listen on 7202 after cutover. This means, if you want to add oacore server2, you must not add it from 7202. However, you can add oacoare_server2 from 7203, if it is free. (it will listen from 7204 after the cutover)
2)During the next adop prepare, the Configuration Change Detector identifies that the addition has been made and the managed servers are automatically synced up from the run file system to the patch file system.