For that combination of people and gear, I recommend the bikes on the roof and a hitch tray. But be sure your exhaust is not pointed at anything flammable!
I put 5 bikes on the roof with Thule load bars and carriers (the full upright style). We have a 4 bike hitch rack too, but as stated above, the differences in top tubes makes it a pain for anything more than short trips. They are also notably short and it is easy to forget that the bikes are another 3+ feet behind you, which changes departure angles considerably. I modified mine to be a foot taller for piece of mind (after I replaced a couple expensive rims once). However the other piece of equipment I keep for the roof mount is a short step ladder. Don't do this option unless you can safely pick up a bike over your head and climb a ladder at the same time.
Good luck!
I put 5 bikes on the roof with Thule load bars and carriers (the full upright style). We have a 4 bike hitch rack too, but as stated above, the differences in top tubes makes it a pain for anything more than short trips. They are also notably short and it is easy to forget that the bikes are another 3+ feet behind you, which changes departure angles considerably. I modified mine to be a foot taller for piece of mind (after I replaced a couple expensive rims once). However the other piece of equipment I keep for the roof mount is a short step ladder. Don't do this option unless you can safely pick up a bike over your head and climb a ladder at the same time.
Good luck!