Arbitration, dicta/holding
Since state law holds that a wrongful death action is held by the next of kin and not the decedent, a release signed by the decedent cannot compel arbitration of the claim.
Arbitration act does not preempt the state law, as the state law does not bar compelled arbitration of the claim.
Rule in earlier holding by state supreme court was an alternative holding, not dicta.
Earlier holding can be retroactive, as it was a restatement of the law, and the state courts have since retroactively applied it.
http://www.ca6.uscourts.gov/opinions.pdf/16a0011p-06.pdf
Since 2011. An occasional commonplacing of the U.S. Circuit Courts of Appeal.
Neither an authoritative statement of the law nor legal advice. Quick work.