Hi,
the 2700€ are just for housing (mortgage) - other region than Karlsruhe..... I'd say 1500€ for a midsize house/flat in Karlsruhe are reasonable (includes the additional charges like heating, electricity....). 2k for the kids' school is too much. We'll pay for our two kids about 1400€/month for private schooling (depends on your annual gross salary). The other positions are reasonable....
Cheers