Isn't this your anniversary trip? Perhaps it would be best if both couples simply reserved a standard room at BWI or regular concierge rooms. That way, neither couple is stuck sleeping on a pull out sofa. I like concierge service, so I would choose the garden suite or that level room. Perhaps it's wise to let the in-laws decide what's best for them. If you only have 2 booked into your concierge room, an option is to have your in-laws listed on your reservation and pay the $50 additional per night for them to have use of the lounge. That way, they can reserve a standard room, everyone has their privacy and all 4 of you can relax with a lovely view from the concierge lounge.