Sorry for the delay in responding. I have long days these days.
As to your question concerning deprecated passages, confessional reformed Protestants (my affiliation) as a whole would not be disposed to include or exclude a passage based strictly on age. That lies more in the direction of those who support the Critical Text (CT).
In general, we reformers follow the Byzantine text type. This is the reason for the preference for the KJV, although as I indicated above not to the extremes of the KJV-Onlyist.
As for your question about age, it would be irrational to use physical age as the sole criteria. A very old manuscript may well be in excellent condition, but perhaps it was regarded as an inferior copy and therefore relatively unused by the active church. So a variety of factors may come into play to determine which text is probably closest to the original.
See for example Acts 2:30 in the following versions:
KJV:
“Therefore being a prophet, and knowing that God had sworn with an oath to him, that of the fruit of his loins, according to the flesh, he would raise up Christ to sit on his throne;”
Douay-Rheims Bible
“Whereas therefore he was a prophet, and knew that God hath sworn to him with an oath, that of the fruit of his loins one should sit upon his throne.”
New International Version:
“But he was a prophet and knew that God had promised him on oath that he would place one of his descendants on his throne.”
Here the Byzantine retains the full force of the language of incarnation, whereas the others, being based on older but arguably inferior texts, tends to reflect an ambivalence toward the connection of the Christ to the physical line of David, which would be expected if, say, Gnostic copyists had meddled with the text. So the Byzantine would here deprecate the CT reading, and in so doing would put us closer to, not further from, classical Christian theology.
In any event, regarding your original question, as I said before, the passages you cite can be read in good conscience by any Protestant without attributing to Mary a state of sinlessness, or any other uniquely Catholic attribution. Given a straightforward use of the Greek, of course.
KJV:
“Therefore being a prophet, and knowing that God had sworn with an oath to him, that of the fruit of his loins, according to the flesh, he would raise up Christ to sit on his throne;”
Douay-Rheims Bible
“Whereas therefore he was a prophet, and knew that God hath sworn to him with an oath, that of the fruit of his loins one should sit upon his throne.”
New International Version:
“But he was a prophet and knew that God had promised him on oath that he would place one of his descendants on his throne.”
It might help to refer to the OT to SEE just what the PROMISE was, to determine how 'close' the NT translations are.