The very first mention and appearance of this character, however, was in Superman #167 (as illustrated in the image here). This is the only appearance of this silver age Vril Dox II. He was later re-imagined (as i like to put it) in the Invasion mini. So understandably many people refer to his 1st appearance as Invasion #1 but i believe it should be Superman #167. I do not have the almighty ability to change 1st appearances so i am appealing to the mods for help. What are your thoughts?
They are the same character. The only thing different between the two is in the original story he was the adopted son of Brainiac while in the newer comics he is actually a clone of Brainiac.They did not specifically call him Vril Dox (he only made a brief appearance after all) but the computer tyrants named him Brainiac 2 which is the other name for Vril Dox II.
Not sure why you say there is very little in common. In both cases, his father willingly served the computer tyrants that ruled their planet which caused him to resent his father. He hated him and wanted to escape Colu, which he ends up doing. Also Superman #167 refers to Brainiac 5 as the descendant of Brainiac 2 (which is exactly what he is in relation to the modern age Vril Dox II)
I wouldn't say those are the only differences, they may have similar back stories but that is it really, they share the code name of Braniac II but Vril Dox is unique, they have different personalities and since Vril Dox is a clone Brainiac 5 is his descendant and the original Brainiacs. It isn't unheard of for creators to know that a character has been used before and just ignores the past and does no research and comes up with a new character, just look at Brainiac 4, original is a woman and then barely a decade later it is a new male character and we get two character pages out of it.
Either way a mod should pop in here eventually and settle things.