I owe the expiation that is prescribed for the delay of missed fasts. Can I pay this expiation for the sponsorship of orphans? Can I give it to the same people but at intervals? Can I pay it to those who perform jihad?

All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

The expiation prescribed for the delay of missed fasts shall go to the poor and the needy, whether they are orphans or whatever else. If the expiation could be delivered to the poor person himself or to his guardian if he is a minor, then this is undoubtedly much better. This is because you will assure that the expiation reaches its nominated recipients. It does not matter whether the expiation is paid all at once or at separate times in case you are required to observe the expiation more than once. Also, one could authorize somebody else to pay the expiation on his behalf to its nominated recipients whether they are orphans or whatever else. Yet, the authorized person needs to be informed that the expiation pertains to feeding the poor and that he is not allowed to spend it otherwise. 

We would like to emphasize that the amount of food to give to each poor person is a mudd of rice. A mudd weighs about 750 gm. The majority of the Muslim scholars maintain that it is impermissible to give the monetary value of the expiation. Rather, the expiation must be given as food. Abu Haneefah holds that it is permissible to give the monetary value of zakah and expiations. Ibn Taymiyyah also agrees that it is permissible to give the monetary value of the food if needed.

Allah knows best.