I wish I had spent more time just playing with them and not so much on teaching in the beginning. Yes, we have to teach and yet I believe a lot more of our bonding came through playing, cuddling, doing fun activities etc. and there is time to teach.
I did stay home and we did delay school.
I informed my family/close friends ahead of time that we would be cocooning as a family and to please not stop by. I actually had a brunch with them beforehand and explained about attachment etc. so they would understand how important it was. I did not introduce them to anyone for a month and then after that month I slowly introduced people over time, and not in a big gathering.
I kept items of comfort they had in the foster home and allowed them to keep them as long as they needed to.
I introduced structure and a daily routine as much as possible from the start. I talked to the foster mom about their routine and used the routine they were already comfortable with and added new steps as they got more comfortable. (I wish I'd asked more details on how they went to bed though as that was an issue in the beginning. I didn't know that our youngest never actually went to bed but had a bedtime snack in his highchair and fell asleep there. They put him to bed while he was asleep.)
I didn't have a language barrier, but a friend of ours mentioned this that might be helpful to you. She played Russian music for her ds when he came home at bedtime to give him familiar sounds/language.
I'll try to think of more...
