This is basically the same response I gave in the last chapter's comments. Surveillance would have identified who Aiden was and where he lived. A human reportedly mated to a wolf would lead to the possibility the human could have been turned. Knowing the human was Aiden's mate, the logical conclusion would be the person living with Aiden is the target, human or lycan. Surname could also be meaningless at that point since it would again be the person living there.
As far as what to do with the kidnap subject, age really wouldn't be a factor beyond the price they could get. Ethan was 18 and strong. As a human he'd only be worth what ransom they could get, had the abduction been a success. A forced turning, had he been human and able to be turned by anyone, would have made him a possible commodity on the shapeshifter black market.
You do bring up excellent points though and it makes me smile when a reader challenges things this well. Thank you, Al