the first question that comes to my mind - why don't the switches have the license? All switches are sold with the Enterprise Pack, which includes trunking. If not, the switches don't seem to be ordered as part of a MetroCluster configuration in the first place or are switches being repurposed for MC setup.
Second - generally OOO is supported, but only if you connect to a DWDM that does not support Brocade frame-based trunking.
Trunking is the default and highly recommended configuration.
If you really want to use OOO I encourage you to get in contact with your NetApp representative to have him file a PVR (product variation request).