Concerning the bad feeling in the basement. I have two suggestions. First speak up and say to whoever or whatever is there that it is time to move on, it is time to find the white light and go in to it and never come back again. Tell it that it will no longer bother this family, Be firm and don't show any fear.
Second, I suggest that you and if you have any friends and or family that feel as you do, need to do a sage blessing/cleansing in the basement. Get all the light you can get down there. If there are basement windows open them. and open windows upstairs. Light sage and let the smoke go in to the corners and in to the rooms. As doing it, say something like this "in the name of God the Father I command you to leave this place. All negative energy is no longer alowed to remain here, all negative energy will be replaced by the light and by all that is good and all that is holy"
You can also make the sign of the cross above each door frame with olive oil. You can also pray over water making it holy and then sprinkle it around the basement.
It is time to take back the livings power over the house and for the dead and the negative energy to leave.
You have more power than you realize.