Hi ricyeunghk2003,
NAT needs to be configured on the Fortigate firewall. There is no configuration case for the Fortigate firewall.
The gateway can be configured on the AC.
Cisco ISE functions as the authentication server. Huawei does not provide a guide for interconnection between Huawei switches and Cisco ISE.
For details about how to configure authentication on the switch, visit
https://support.huawei.com/hedex/hdx.do?docid=EDOC1100126530&id=EN-US_TASK_0176368904&lang=en.In addition, you are advised to contact pre-sales personnel for more help.