Inviting only some out of town guests to rehearsal luncheon?

So I'm not quite sure what the etiquette on this would be. We're trying to keep the rehearsal lunch (rehearsal is in the morning) small since FH and I are paying for it ourselves. On the guest list, we have the whole wedding party including their spouse/partner and kids, our parents, and officiant. The only trouble is, one of my bridesmaids is coming from out of town. She's my cousin so obviously my aunt, uncle, and other cousins are also invited to the wedding. But should they all get an invite to the rehearsal lunch as well? The other thing is she doesn't drive, so my aunt would likely be bringing her to the rehearsal. It seems rude to have them just drop her off while they go back to their hotel or eat someplace else when they could join us.