I am not up on the latest trends, but in the past we have unofficially sponsored some underprivileged families, usually the undocumented type so they weren't on official lists. So I am not sure if your just doing toys for tots or actually someone you know.
What we found. The living situation often means minimal space, living with others, or moving frequently. So while I love the idea of Lego's - they would be likely to get lost in the scenarios I am familiar with - too many parts. Also anything requiring batteries is not good - they will never get replaced. Integrated rechargeable might be OK, but include a extra cord. We stuck with things that were hard to break and easy to keep track of - Tonka trucks, hot wheels, sporting goods like soccer balls, etc.
Bikes are appreciated. Include a helmet.
Not so much for 8 year olds, but kids approaching teens often wanted clothing - because they had so little.
Good luck. Your a good man!