Is the Soloy Dual Pac recognised as two engines or one engine?
According to the certificate is a


  Twin Power Section Turboprop


and, later, note 7: (emphasis mine)


  This engine is certificated as a unit comprising two separate power sections with the capability of single engine operation with either power section alone in multi-engine airplanes. The unit is also approved as a single engine with either or both engines operating continuously. 


No explicit remark is given about pilot licensing, but given the note reported, I would say that a licence for a single engine is sufficient.