Questions as to who constitutes dependents and the extent of their dependency shall be determined as of the date of the injury to the employee, and their right to any death benefit shall become fixed as of such time, irrespective of any subsequent change in conditions except as otherwise specifically provided in sections 321, 331 and 335. The death benefit shall be directly recoverable by and payable to the dependents entitled thereto, or their legal guardians or trustees. In case of the death of a dependent, his proportion of the compensation shall be payable to the surviving dependents pro rata. Upon the death of all dependents compensation shall cease. No person shall be excluded as a dependent who is a nonresident alien. No dependent of an injured employee shall be deemed, during the life of such employee, a party in interest to any proceeding by him for the enforcement of collection of any claim for compensation, nor as respects the compromise thereof by such employee.