1. When you say WiNG AP is configured with DHCP IP for VLAN 1 which is the native VLAN for ge1.
It is the case when the switchport has no config on it? Correct me if I'm wrong?
>> I'll assume that you are referring to AP int ge configuration, and the default behaviour is as below:
interface ge1
switchport mode access
switchport access vlan 1
interface vlan1
ip address dhcp
ip address zeroconf secondary
ip dhcp client request options all
2.If we want APs to get IP address from a different VLAN, say VLAN10 and WLAN users on VLAN20. Do we need to configure the switchport as a trunk port with native VLAN as VLAN10?
>> Yes, on top of that you will need to configured AP interface ge1 to allow VLAN 10 and VLAN 20
For example:
interface ge1
switchport mode trunk
switchport trunk native vlan 10
no switchport trunk native tagged
switchport trunk allowed vlan 10,20