Vias in a footprint using Eagle
Apparently, Eagle doesn't allow vias in footprints (only pads).  Markers will work to check alignment, but for creating them you can write a script that takes the part designator as parameter, and uses it to extract location and rotation to place the vias at the correct coordinates. Something like place_bpf_vias(part_designator)

Because the vias are not linked to the part, you will have an issue when moving it, so first select it with the vias as a group.