Is it permissible to accept sadaqah for minor, well-cared-for orphans, and can it be given to other needy individuals if the answer is no?

If the funds given to the orphans are from zakat (definition), then it is not permissible to accept them if the orphans are wealthy, because the wealthy are not among the recipients of zakat. They must be returned to their owners so that they can distribute them to those who are deserving. The guardian is not permitted to spend them due to the lack of intention [for the specific recipients]. However, if they are voluntary charity (sadaqat tatawwu') or gifts, then it is permissible to accept them, and it is recommended for the wealthy person to refrain from them out of piety.