Re: spray foam insulation
I agree pretty much with jkirk .... the open cell will breath.
Also the foam itself isn't food for mold.
As for putting the fiberglass batts over top of the foam .... this shouldn't be an issue.
It will add to the overall insulation value in your attic .... besides it's a recycle situation I agree with instead of just tossing it away . Also it didn't cost you anything and it doesn't cost a dime to use .... so why not reuse it.
BTW .... around here R50 is becoming the norm.
"" an ounce of perception -- a pound of obscure "