I find the question interesting because of work I have done on Phil. 2:6ff. Granted, the Philippians text is vexed with exegetical issues and one has to concede that μορφή could denote "status" rather than "external appearance" in Philippians. However, one has to ask whether the Philo text really has any bearing on what Paul wrote. Secondly, how should Philo be interpreted?
One translation of Philo reads: "What connexion or resemblance was there between him [Gaius] and Apollo, when he never paid any attention to any ties of kindred or friendship? Let him cease, then, this pretended Apollo, from imitating that real healer of mankind, for the form of God is not a thing which is capable of being imitated by an inferior one, as good money is imitated by bad."
Hurtado also quotes Embassy 114: "Have we not, then, learned from all these instances, that Gaius ought not to be likened to any god, and not even to any demi-god, inasmuch as he has neither the same nature, nor the same essence, nor even the same wishes and intentions as any one of them"
From these passages, Hurtado extracts the idea that Philo might have divine moral/ethical attributes of deity in mind. But does he?
The late Dr. Rodney Decker writes:
Lightfoot is a classic example of those who base the meaning of μορφή on Greek philosophy. He explains that it refers to "the specific character" (129); that "μορφή must apply to the attributes of the Godhead" (132). "In Gk philosophical literature, μορφή acquires a fixed and central place in the thought of Aristotle. For him the term becomes equal to a thing's essence (οὐσία) or nature (φύσις).”1
However, Decker provides ample reasons to reject this understanding of μορφή in Philippians 2:6. We also learn that Hurtado's suggestion isn't new after all since Lightfoot thoroughly plumbed Philo, Aristotle, and other writers to examine the potential denotation of μορφή, and his view of the word fell along similar lines as Hurtado's. Yet Lightfoot was almost surely mistaken or at least only partially correct as I have pointed out in the first volume of Christology and the Trinity and so has Moisés Silva in his Philippians commentary.
For Decker's analysis, see http://ntresources.com/blog/documents/kenosis.pdf
Concerning "the specific character" understanding of μορφή, Lightfoot himself maintains that the ancient Neoplatonists and Philo both knew and utilized the word in this manner. See Lightfoot's analysis at https://archive.org/stream/cu31924029294398#page/n145/mode/2up/search/philo
Nonetheless, I emphasize that Paul likely did not use μορφή this way. Both Moulton-Milligan and BDAG support this contention.
Hurtado's discussion is here: https://larryhurtado.wordpress.com/2017/04/19/the-form-of-god-philo-and-paul/#comments