Apocatastasis in Milton?

(Image: Hieronymus Bosch, The Earthly Paradise (Garden of Eden), c. 1504, borrowed from Nicolas Pioch, WebMuseum Paris: Bosch, Hieronymus: The Garden of Earthly Delight)

Does Milton subtly insinuate into Paradise Lost the doctrine of apocatastasis, the teaching that all of mankind (and sometimes fallen angels, too) will be restored to God?

In Book 3, lines 274ff of Paradise Lost, Milton shows God the Father commending the Son for volunteering to take human nature upon himself in his role as messianic redeemer:

O thou in Heav'n and Earth the only peace
Found out for mankind under wrauth, O thou
My sole complacence! well thou know'st how dear,
To me are all my works, nor Man the least
Though last created, that for him I spare
Thee from my bosom and right hand, to save,
By loosing thee a while, the whole Race lost. (PL 3.274-280)

What struck me were the words that God allows the Son absence from heaven "to save ... the whole Race lost."

Taken alone, these words imply that God saves every human being through the Son. Is this Milton's view?

Based on other passages in the poem, I'd have to conclude that Milton does not subscribe to apocatastasis. He presents God as extending salvation to each human being but also has already shown God informing us that some will scorn God's call of conscience:

And I will place within them as a guide
My Umpire Conscience, whom if they will hear,
Light after light well us'd they shall attain,
And to the end persisting, safe arrive.
This my long sufferance and my day of grace
They who neglect and scorn, shall never taste;
But hard be hard'nd, blind be blinded more,
That they may stumble on, and deeper fall;
And none but such from mercy I exclude. (PL 3.194-202)

Some will (freely) "neglect and scorn" God's offer of grace and therefore be excluded from God's mercy.

This would seem to settle the matter: some human beings remain lost.

I therefore conclude that when Milton has God the Father tell the Son that he will allow him absence from heaven in order "to save ... the whole Race lost," Milton intends us to infer that although saving all human beings is God's intention, God's divine will can be thwarted by the free will that he has also granted human beings (cf. PL 3.124).

Milton thus does not go quite so far as William Langland in Piers Plowman 18.408-416.