Moving to Frankfurt

Dear all, my wife and I have an opportunity to move to Frankfurt. The job itself is in Aschaffenburg, but my wife speaks English and Cantonese only and is desperate to have international friends instead of all day Kopfschmerzen. Also, our children are or will be speaking Dutch and English with a good understanding of German and Cantonese. Frankfurt should be our residence for the coming 5 years. My questions are mostly around the cost for the kids: one is 3 years, the other one 3 months.

Cost for day care, school fees at English or bilingual speaking institutions?
Tips where to live and cost for an at least 120m2 apartment or house?

Would be great to hear some really great tips from you.

Regards,

Amy, Emily, Connor and Stephan