For ZD, this thread:
would suggest to me that there's one NIC controller not two so aggregating/combining the two ports would not give you any benefit.
Also since the ZD is only for config/info/control data you'd have too have huge numbers of APs to stress it's ethernet port.
As for APs well depends on the model...the more expensive ones might have seperate controllers.
As always...I could be worng (or even wrong)!