It's true that Harry's not in the most secure of positions. I hadn't really considered it that much, because I always assumed that Sirius had enough money to make any problems pretty much disappear. Certainly the Dursleys would never fight to get him back unless he were worth something. And, while we haven't heard the end of the Dursleys in LC, they certainly won't be going after Harry anytime soon.

Anyhow, adoption will also come up again, in its own time. And anything more would be spoiling the story....:D