As foster parents you know what it's like to bring a new person into your home. This child will have his own issues and you will have to have great patience. I am going to assume some things, if I am wrong then just take it with a grain of salt...LOL.
If he is coming in a few days then he is already in the system. Depending on how long he has been in care will determine his mental status, if he's in mourning/loss, etc...if he's realized he's better off, if he expects to go home or age out.... The person he is is a product of the life he has experienced.
The child that will be joining your home will obviously need time to blend into your schedule. I think your Summertime schedule sounds fine. I would encourage him to go to bed around dark and let him have some unwind time like the bigger kids. If they are going to share a room he'll need to have the same schedule. Summer in the middle of the USA makes dark around 9:45. I was sent to bed at 8:30 during the elementary school years and all the neighborhood kids would sit outside my window on their bikes and make fun of me for being in bed. Once time change sets in the bedtime should definitely be earlier.
He probably has never had to do chores except in a previous foster home. I would think it would be good if you could visit with the previous foster parents and see what they have to say about it. I think simple chores at first, see if there is anything he likes to do, I love doing laundry, my husband doesn't mind doing dishes, it works for us because I would rather buy new dishes instead of washing them. He might like being outside and working in the yard and he might have lived in an apartment with no yard, ever. So many variables can influence him. Your just going to have to visit with him after a day or two of settling and ask him. I think he'll need supervision at first to learn how you like things done. My friend has notes posted in each room and they follow a simple format:
The kitchen is finished when: The counters are wiped down and free of dirty dishes, the dishwasher is loaded and running, the clean dishes are put up in the cabinets, the floor has been swept and any spills mopped up.
The littler kids could be paired with the little kids and big kids too, the littler kids could empty the silverware into the drawer while the dishes were being put up, the little kids emptying the bottom shelf of the dishwasher and the big kids the top shelf and drainer. They can hold the dust pan while a bigger kid sweeps, etc...he might really enjoy "teaching" someone how to do something and it could build his self image and self worth.
The point is the family worked together to mentor the younger kids and to promote a clean living environment.
A "big" kid and a "little" kid are paired up to work in a large room together. Littler kids are the youngest around that show an interest in helping out up to around. She had 7 kids so there was always various ages working together.
You sound like you have a good understanding about the children in your care. Good luck with your new addition.