Since their dogmas don't come close to matching up (V'Ger was to see all it can see, learn all it can learn and return that information to the creator, whilst the Borg seek to achieve dominance and perfection through the assimilation of other species and their technology) I'd say that the two have nothing to do with one another.
If V'Ger was of Borg origin why wasn't it swarming with drones, assimilating every planet and ship it came across? Ilia Probe wasn't an assimilated version of Lieutenant Ilia but an artificial life-form in her image, which the Borg doesn't do--they combine organic with cybernetic (then even did it in reverse when they tried to entice Data to join them). Even Decker's merging with V'Ger wasn't any kind of assimilation more a symbiotic joining of its knowledge and power with his imagination and creativity.
And you think exactly the same as your cousin? If they're related, say by a common connection to the machine planet, where the machine planet upgraded both of them at different times, then they'd be recognizable to each other as distant kin, yet be totally different ideologically. Yours was a false argument.
Different ideas do not equate to no relationship. Doesn't make them related, it just doesn't have anything to do with whether they are or are not.