After a little bit more digging I've noticed that the IP addresses that are being picked up from the WAPI call have a Lease state of 'Free' where as all of the other unused IP addresses have a Lease state of 'Abandoned'.

Thanks for the response. Looks like I was working on an older infoblox appliance. (WAPI 1.72). You are right, I see it on the new appliances. Yay!. Thank you.

I do not have the python code handy, but below are examples for setting options...