You have the option of configuring the IP address of the WDS on the Infrastructure APs, but I don't remember if it allows multiple adresses for redundancy. Let us know.
Since you're deploying virtual gateway, you probably want 1:1 ratio for Auth and Access VLANs. This is also better for Spanning Tree - you should limit you VLANs at each closet, and manually prune them "switchport trunk allowed vlan #,#,#"Typical exa...
