Jeff,
Will souls in hell at the moment be able to receive intercessions from us living?
YES. Souls in hell can be saved by prayers and almsgiving. If you hear the prayers, it will be self explanatory. Prayers in the Orthodox Church can answer many of your questions.
One prayer for the dead: "give rest to the souls ... that have fallen asleep, in ... a place of refreshment; ... . for the dead shall not praise Thee, O Lord, neither shall they that are in hell make bold to offer unto Thee confession. But we that are living will bless Thee, and will pray, and offer unto Thee propitiatory prayers and sacrifices for their souls."
This is a concern that many who contemplate the afterlife have, including myself. I've read many Orthodox sources about this issue. I don't know if you are familiar with the website orthodoxlife.com, but it has many articles. You can search for them by keywords. This is what I have read there. Perhaps it will give you more insight about it.
http://www.orthodoxinfo.com/death/prayer_dead.aspx
Take the time to read it. Further into the article, it describes events of saints(who still lived here)and what they witnessed. Prayers and almsgiving can liberate a soul from the eternal torments of hell. That is why the holy fathers have established prayers for the dead, including those that might have been judged worthy of hell.
will God here people in hell?
.
NO
Souls in hell cannot pray for us. They have lost their rights, if you will. The destitute in the streets can not provide financial support for us, can they? They can not pay our bills or feed us. So how can a soul that has foresaken God, is spiritually destitute, be heard by God? They made their choice. Their hearts turned away from God and therefore they end up in the place that their hearts can only accept, which is distant from God. There's a passage in the New Testament...Luke 16:20 that describes the state of Lazurus' soul, the rich man, in hell. And he begged God to send the beggar to his brothers to warn them, but God would not oblige him.
All the answers you want are in the Holy Bible. You just need to recognize them.
even if all of those people whom we thought were "saints" or "Agion" were locked in a prison somewhere in another plane of existence are able to listen to our prayers or memorial services
Is there a particular saint or saints that you refer to? This is a curious question. How can we know that a soul is "locked in a plane" somewhere.