Who wrote the gospel attributed to Matthew?

[jeremyp]

John 2:11 "This, the first of his signs, Jesus did at Cana in Galilee, and manifested his glory. And his disciples believed in him". ESV

Disciples referred to in the third person again. Not the author.

[Spud]

Christians. You keep banging on about it all the time.

The first line of the Battle Hymn of the Republic "Mine eyes have seen the glory of the coming of the Lord". Do you think Julia Ward Howe was one of the disciples?

Meyer says,

It [his glory] presented itself to the recognition of believers as a reality, in the entire manifestation, work, and history of Him who became man; so that they (not unbelievers) beheld it[98] (intuebantur), because its rays shone forth, so as to be recognised by them, through the veil of the manhood, and thus it revealed itself visibly to them (1 John 1:1; comp. chap. John 2:11)

Which seems to be saying that beholding his glory is the result of the Word becoming flesh, and being seen by them. You're probably right that the 'we' is not just the disciples; it is the community of believers who saw Jesus in the flesh.
This implies the writer was an eyewitness, as per the first point in the list. Note that Meyer says "comp. Chap. John 2:11"

[Spud]

Disciples referred to in the third person again. Not the author.

That doesn't preclude the author being one of the disciples.

[jeremyp]

Meyer says, Which seems to be saying that beholding his glory is the result of the Word becoming flesh, and being seen by them. You're probably right that the 'we' is not just the disciples; it is the community of believers who saw Jesus in the flesh.
This implies the writer was an eyewitness, as per the first point in the list. Note that Meyer says "comp. Chap. John 2:11"

No it doesn’t imply the writer is an eye witness nor does it imply the “we” is the group who saw Jesus before he died. Furthermore, there’s still the problem that the key people, if John is the author, are described in the third person.