Sc. 2.
"Who had no doubt some noble creature in her."
If 'creature' is not a collective, it is a misprint for 'creatures.'
"Was duke of Millaine, and his only heir
And princess, no worse issued."
Pope read, I think correctly, 'A princess.' We have, "And marriage" for "A marriage" (Hen. VIII. ii. 4). See also on Jul. Cæs. v. 2.
"And to my state grew stranger."
We should perhaps read 'a stranger.'