How can I have two users on one account,

You can set up multiple email accounts on each device. You also dont have to use your apple ID email account as an email account but still use it for iTunes on each iPad.

 

They really don't advertise this either, but you can have multiple emails assigned to an Apple ID as well. I use the same single account for the household and wanted to see how I could use iMessage for everyone with only the one Apple ID. I found that I could associate an email with the account for each person in the family (only 4 so not exceeding the device limitations) and then edit the information each device saw and only limit it to the email for that user, which is already associated with the Apple ID (not the main email for the account). This way everyone has their own email address, but can use all of the features of the Apple ID account as if it were their own specific account (except for the iCloud backup which we don't use as everything is backed up to my server). This allows the purchases to be shared between the devices and limit the number and need for excess purchases.