First, this clearly is intended to be a prophecy. Second, there is no doubt that this prophecy can be seen as and was thought of as being about the final resurrection. The question, then, is whether this is a “double prophecy.” Of course, there are those who say there is no such thing as a double prophecy, but there are dozens of examples of this. Matt 24 is a very obvious example, as it is a prophecy both of the destruction of Jerusalem and of the second coming of Christ. There are many “double prophecies” in Ezekiel. For example, Ezekiel 36 22-38 is unmistakably a double prophecy about the return of Judah from Babylonian captivity and about the New Covenant in Jesus.
But getting back to Isaiah 25:6-8, this prophecy is more vague as to its details, and therefore as to its application. However, his use of the mountain of the Lord makes me think that God has in mind fulfillment in the Church and the coming of the kingdom in the form of Jesus. I say this because the mountain of the Lord is clearly about the Church in other passages in Isaiah, such as 2:1-5. Also, he talks about a feast “for all peoples.” Again, this makes me think about the Christian Church. The prophecy in Isaiah 2:1-5 and many others predict all nations and peoples coming into God’s kingdom when the Church was established. Also, he says that “he will destroy the shroud that enfolds all peoples.” I cannot prove this, but it is suggestive of the fact that in Christ all the mystery of God is revealed (Colossians 1:26).
By the way, Bailey’s argument using Luke 14 is another valid one in support of the dual prophecy idea. Of course, the kingdom parables as told by Jesus are primarily about the Church and salvation in Christ, but even some of these parables can be seen to refer both to the current version of the kingdom (the Church) and the future kingdom of God in heaven.
So, my answer is that I agree with your thesis that this is a double prophecy. I believe that some Jews would have seen fulfillment of this prophecy in the return from captivity from Babylon, but the details do not line up as well as they do with the two applications you are making. One can argue that this is a specific prophecy about end times and/or about the Church, but that it is also a general statement about anyone who accepts Jehovah as king in any setting.