If we accept the possibility that in fact the ancestors do live among us, the question is, 'Do these ancestors interact with us? In particular, do they speak to us?'
African culture and religious belief relies heavily on the concept of guidance by the ancestors. They believe that ancestors speak to them in their dreams and direct them. While western Christians talk about the call of God on their lives, Africans will speak of the call of the ancestors. I am not sure whether the church, by and large, has managed to differentiate between these two ideas of calling.
Now, what does the Bible say about the dead speaking to us?
We have the Old Testament prohibition against consulting the dead - which Saul defied when visiting the witch of Endor. We also have Hebrews 11:4 which says that Abel, though dead still speaks. We have the Lord's refusal to allow the rich man to warn those still alive of the future consequences of their actions. We have the meeting between Jesus, Elijah and Moses on the mountain of transfiguration.
In cases where people are spoken to by spirits these are always referred to as dangerous, if not evil - and there is no case where the spirit is permitted to remain. There are so many instances of spirits being cast out that I don't think I need to list them!
Perhaps I should mention three other 'experiential things'. I don't believe that I have ever conversed with a dead person. I do believe that when someone has experienced the loss of a loved one there is the tendency to believe that the loved one is around, watching over them and listening to them. The Roman Catholics' belief in the intercession of the saints may come into this discussion somewhere.
However, I cannot come to the conclusion that the Bible admits of safe, healthy interaction with the dead. The trend is to warn us away from 'other' spirits. So, if the dead are living amongst us communication with them is not the norm - to say the least.
It occurred to me after writing this that I have not taken angels into account. Angels are really God's messengers - could he use ancestors in this way? It is possible - although then one would assume that the ancestors are living with God (as we know the angels do) and not among us.