During an Avaya IP Office Installation, an Auto Attendant can be tested by calling the Voicemail Start Code *77. This will launch the Auto Attendant and allow you to test it to make sure it is working correctly. Dialing the default Short Code *91#, the Voicemail Announcement Code *8101, or creating and dialing a new Auto Attendant Short Code will not launch the Auto Attendant and will not allow you to test it.
Reference:
Avaya IP Office (https://www.avaya.com/en/solutions/ip-office/).
Avaya IP Office Voicemail Pro (https://www.avaya.com/en/solutions/ip-office/voicemail-pro/).

To program an Incoming Call Route (ICR) to meet the requirement of routing all incoming calls from the 212 area code to the Sales hunt group, two steps are needed:
Enter 212 in the Incoming Number field.
Add an ICR for Any Voice with the destination of the Sales hunt group.
The Receptionist hunt group should not be selected as the fallback extension, and the Incoming CLI field should not be used.
Reference:
Avaya IP Office (https://www.avaya.com/en/solutions/ip-office/).
Avaya IP Office Incoming Call Routing (https://www.avaya.com/en/solutions/ip-office/incoming-call-routing/).

The IP500 V2 control unit can support up to 8 external expansion modules without adding a 4-port expansion card. Adding a 4-port expansion card would allow an additional 4 external expansion modules to be added, bringing the total number to 12.
You can refer to the IP Office Technical Bulletin Number: TB-6401 which is available on the Avaya Support website, to get more information about the IP Office System Capacities.
Reference:
Avaya IP Office (https://www.avaya.com/en/solutions/ip-office/).
Avaya IP Office Capacity Planning (https://www.avaya.com/en/solutions/ip-office/capacity-planning/).