Re bedroom -make sure you say they can choose their own duvet cover, pictures for the wall , show plenty space for their toys and clothes they will bring with them.
Contrary to popular belief, many foster kids have LOADS of stuff, clothes and toys. Especially if they have been with the FF for a while . Make sure there is space and storage .
Ask the foster carers what they like to eat and take some photos of you eating their favourite meals. There's bound to be something you have that they like at the FC, even if it's just a plate of cornflakes. Kids of that age can worry that they won't like your food.
show your bathroom and point out ( if it's true ) that you have and shower and a bath so they can chose which they want to have.
Find out from FC what they like to do and be sure to mention it eg photo of swings in park, local swimming pool, football, dancing , rainbows
Go easy on the extended family, it can be a bit intimidating. A new mum and dad is quite scary enough . Ditto where you work, most 5-6 year olds don't care .unless you are something interesting like a premier league footballer or an airline pilot or train driver or work in macdonalds .
Also they will worry who will look after them while you are both at work
My kids are 8 and 9 and they wouldn't relate to maps or floor plans . Video idea is great as 5-6 year olds probably are only beginning to read themselves .