Wisconsin isn't a piggyback state, but it wont get processed until the federal return has already been accepted.  This chart might help.

https://proconnect.intuit.com/community/individual/help/ef-atlas-federal-state-ef-method-standalone-...

You could try attaching a copy of the federal return as a PDF to the state return and Efile it, se what happens.   Youre paying to print or file the federal return, so yes, if the state needs a copy of the federal, you'll need to pay for both.