We don’t know many of the details of the kingdom, but during the kingdom (the ‘1,000 years’ reign of Christ on the earth — Rev. 20:4; 5:10), and even after the kingdom (when God is ‘all and in all’ — 1Cor. 15:28), the saints will probably still be known by their names. We can see this in the existence of the angels — who dwell with God (Mat. 8:10; Mark 13:32; Luke 1:19),1 are at one with him (Ps. 103:20), and yet still have their own names (Dan. 9:21; 12:1; Luke 1:19)2 — and, even more so, in the life of the Lord Jesus, who dwells with God (Acts 7:55),1 is one with him (John 10:30), and still has his own name (Phil. 2:10), the name he had while a flesh and blood human like us.
A few passages talk about people’s ‘names’ being written in the ‘book of life’ (Phil. 4:3; Rev. 13:8; 17:8; 20:12; 20:15; 21:27). Although this is talking about more than just a ‘name’, it’s probably safe to say it also means the saints will keep their actual names.
The one who conquers will be clothed thus in white garments, and I will never blot his name out of the book of life. I will confess his name before my Father and before his angels. (Rev. 3:5)