Is it a permanent move, or for x years for work?
Dh and I lived abroad for 13 years, including when dds were small. Ironically enough, though, both my parents and the in laws probably saw more of us all in total through the year, than they did of other dcs/gdcs who were scattered about the UK, since we stayed with them on annual leave, and both sets of parents came and stayed with us for at least a couple of weeks at a time.
As for gifts, I would ask. Maybe they won't know what they might want just yet.