H1B extension: also provide both I485 information.
AP renewal: Only link AP to EB1b-I485. In the cover letter should mention the I485 is based on EB1. Of course the USCIS will track your both cases through A#. I have only one A#. Otherwise should use A# on your EB1-I485.
Similarly,On the whatever cover letter when you contact USCIS, refer your I485 based on EB1.
Hope this will be of some help.