These consolidated bankruptcy appeals arose from a global dispute between the Redmond and Zeltser groups over ownership and control of three involuntary Chapter 11 debtors: Fisher Island Investments, Little Rest Twelve, and Mutual Benefits Offshore Fund. The bankruptcy court resolved the ownership issue in favor of the Redmond group, entered summary judgment concerning Fisher Island and Little Rest, and later entered final judgment concerning Mutual Benefits. The Eleventh Circuit affirmed all orders. It held that the ownership question was a core matter because the bankruptcy court could not administer the involuntary cases or determine whether they were contested without first deciding who owned and represented the alleged debtors. Even if the matter were non-core, the Zeltser group had expressly consented to the bankruptcy court’s adjudication and waived a contrary objection through months of participation. The court also held that the ownership dispute properly proceeded as a contested matter, not an adversary proceeding; the parties received adequate notice and an opportunity to be heard, and mandatory joinder did not apply. The bankruptcy court properly granted summary judgment after giving the Zeltser group a chance to address the proposed ruling. Non-party appellants lacked the financial stake required for bankruptcy appellate standing, and the Mutual Benefits judgment was supported by the record.