Matt. 19:27,28 & Lk 22 speak of the Apostles ruling the 12 tribes of Israel
27 “Look,” Peter replied, “we have left everything to follow You.
What then will there be for us?” 28 Jesus said to them, “Truly I tell
you, in the renewal of all things, when the Son of Man sits on His
glorious throne, you who have followed Me will also sit on twelve
thrones, judging the twelve tribes of Israel."
Also, Luke 22:28-30
"28 But you are those who have continued with Me in My trials. 29 And I
bestow upon you a kingdom, just as My Father bestowed one upon Me,
30 that you may eat and drink at My table in My kingdom, and sit on
thrones judging the twelve tribes of Israel."
From the commentary found @ BibleStudyTools.com
Not only will the saints reign with Christ, they will also judge with
Him (Rev. Rev. 20:4+). It is important to realize that even though the
saints will perform judgment, this will not be the dominant activity
during the Millennial Kingdom, at least not in the sense of meting out
punishments. [See George H. N. Peters, The Theocratic Kingdom (Grand
Rapids, MI: Kregel Publications, 1978, 1884), 2:352-361]
It appears that Jewish saints—the resurrected apostles—will judge over the twelve tribes, the nation of Israel. At that time, all ten tribes will be present and accounted for.
Acts 1:12-26 details the appointing of the Apostle to replace Judas.
Especially look at verse 16, then 20... quoted here:
20 For it is written in the book of Psalms, Let his habitation be
desolate, and let no man dwell therein: and his bishoprick let another
Continuing, verses 22-26
22 Beginning from the baptism of John, unto that same day that he was
taken up from us, must one be ordained to be a witness with us of his
resurrection. 23 And they appointed two, Joseph called Barsabas, who
was surnamed Justus, and Matthias. 24 And they prayed, and said, Thou,
Lord, which knowest the hearts of all men, shew whether of these two
thou hast chosen, 25 That he may take part of this ministry and
apostleship, from which Judas by transgression fell, that he might go
to his own place. 26 And they gave forth their lots; and the lot fell
upon Matthias; and he was numbered with the eleven apostles.
So then, from this account in Acts it seems quite clear that the reason they were deliberating over two, though it could easily be understood that there were more who had been with them from the beginning, was because of their interpretation of Psalms as it related to Judas. They felt, obviously through the guiding of the Holy Spirit as they had just received it as Jesus had said they would, that this was the correct interpretation and course of action.
As far as when:
Some would say the events of the early chapters of Acts occurred during the decade of the AD 30's.
The Book of Acts (of the Apostles) was supposedly written between 61-64 A.D. according to this site https://gotquestions.org/Book-of-Acts.html
The controversy that might be had—could be had at Shaul/Paul's assertion that He was an apostle, equal in every way to those
hand picked by Jesus. Romans 1:1, 2 Timothy 1:1, Ephesians 1:1,
1 Corinthians 1:1, all include his greeting saying he is an Apostle specifically of Jesus, the Christ.
Shaul's first missionary journey, according to one source is dated between 46-48 A.D.
According to the same timeline, the author has Herod Agrippa I's order for James' execution occurring at the year 44 A.D.
So if you wanted to make a case for Paul replacing James the onus would be yours, but the Scriptures do not seem to hint
that a tradition of having precisely 12 living Apostles at any one time after the appointment of Matthias, existed.