The toolbox, as it says in its description if you click on it in the store...
helps prevent leaking/clogging issues (they won't happen as much if you buy the toolbox
The lawn chairs (aka Patio) - Yes, our friends can sit in the chairs, and I'm not certain, but I think I caught a glimpse of one sleeping in the patio chair

Bird House - advantage - I think it's terribly cute to listen to them whistle at the birds. Otherwise, none found personally by me. You never know though.
BBQ - They certainly can, and seem to enjoy the activity. However, I can not vouch for them eating BBQ'ed food or it helping with their "Fed" Bar.
