Of the many wonders and signs Jesus performed to provoke faith among His followers in the 40 day interim from His Resurrection to Ascension, the Gospel writers chose to include only a few of His appearances (for obvious reasons):

And so we have 10 separate commonly held accounts of Jesus' pre-ascension appearances recorded in the New Testament, plus 3 post-ascension:

There were many appearances other than these recorded, some likely to His own family since they were non-believers before the resurrection and later seen present in the upper room awaiting Pentecost with the other disciples. ( Acts 1:3, Acts 1:14)

One cannot say for sure if this was the appointed Galilean appearance, but we can say by their remaining in Jerusalem, they failed to comply with His command immediately because of their unbelief, requiring Him to first appear in Jerusalem, upbraiding them for this and their hardness of heart. (Mk.16:11,14)

Apparently, they all are now in faith and compliance, including Thomas, who has ascended the list, preceded only by Peter. (Tradition has him being a great teacher in the Church at Jerusalem, second to none. - Eusebius, 3rd century historian. See "Thomas," p. 26 of Appendix.) Only 7 are present at this appearance, due likely to their being from this area, while the remaining 4 absent to their own homes in other regions.

Only Peter, Thomas, and Nathanael are named, but we know the sons of Zebedee to be James and John (our writer), with the remaining 2 likely Andrew (brother of Peter) and Philip (friend to Nathanael). Thus, we see John closing his gospel with the original 6 disciples introduced in Ch.1, plus Thomas -- now an avid witness. This is not an accidental inclusion, for John is clearly showing that the first 6 who believed in Jesus from the outset of His ministry (shortly following His baptism) are still united in belief to this cause they have permanently surrendered their lives to plus now joined by, who many say was the greatest skeptic among the 12, Thomas, thus lending greater validity to their collective testimony to the life of Jesus. Also, from a writer's standpoint, employing a scene similar to his opening with the same characters in a concluding scene, quite naturally ties together his writing for the reader in a fulfilling conclusion.

Our time now is some days beyond the first week of Jesus' bodily resurrection. He has appeared already to all eleven remaining disciples, plus many others. Earlier, these had enjoyed constant unbroken contact prior to His crucifixion, but now Jesus is preparing them for His permanent and final physical withdrawal by only occasional contact. He appears to them at will, usually unannounced, and sometimes in varying unrecognizable forms. (Your additional thoughts here of His new outer garments previously discussed in Ch.20.) Whatever His body, He apparently has the ability and quality to disguise Himself from within in many ways, no longer dependent upon external Earthly corruptible attire!

As previously stated, these terrestrial followers must be convinced of His Heavenly body, unique from all others resurrected by His call previously seen, His no longer constrained by the laws of nature, now having overcome man's final natural act in life: Death. This done so as to secure faith for hope of their own future resurrection unto immortality, freed finally from the restraints of this world's capture. (I Co.15:12-20)

It is apparent His appearances are reuniting them after scattering separate ways following His death. Their past customary closeness in daily ministry, now giving way to a new method of meeting and service, will eventually evolve from their past itinerant ministry to the future local based missionary-minded Church. They again will return to their own lives, but remain closely connected as one body in His Spirit sent for their care, growth, and outreach. They must have time to adjust to this new way in His physical absence, yet remain dependent upon His Spiritual presence while expecting His imminent visual reappearance, or return. And so they lived! As we also should today! Hence, He remains 40 days, and, at times, days pass between His appearances. ( 14:16, 20:26)