Can I buy house from deceased parents estate and get $8000 tax credit? I would be buying out brothers & sisters.

I believe you can. Since the house is in the estate it effectively belongs to you and your siblings. You CAN buy a home from your sibling(s) and still qualify for the credit - the prohibition against buying from a relative applies to purchases from your spouse, ancestors (parents, grandparents, etc) or your lineal descendants (children, grandchildren, etc).