Can parents who are separated both have access to their child's Pageticker account?

Yes, they can both have access to the parent app and link with their child. 

On the teacher dashboard, you can create parent letters at any time. Each letter has a couple of one time only codes. You just need to make sure that they don't use the same codes on the letter. As once a code has been used once it will no longer work. 

If the codes on the letter haven't been used then the expiry date will be extended. If the codes have been used then new ones will be created when you regenerate the letter. 

If you just want to generate a code, then you can do this on the teacher dashboard by clicking on the name of a pupil and generate a new code. 

On the settings page, they'll be able to see that the other parent is linked but won't be able to see their email address or any contact details.