Teknia (a diminutive). It is a term of parental affection. It applies to Christians irrespective of growth. Used in vers. 12.28; chs. 3.7,18; 4.4; 5.21; John 13.33; Gal. 4.19
John uses 'hour' continually in the sense of 'time,' as John 5.35, 'a season.' It is properly a given point of time. With John it is constantly a period characterized by one thing, and hence looked at as only one time. As we say 'the hour of Napoleon's greatness.'
'There have come' (ginomai: John 1.17) is not from the same word as 'comes' in this verse. It is what did not exist before, but begins or becomes. 'There have come' I believe nearest the sense. The perfect tense conveys the thought that they still exist.