@Level-With-Me Regarding the Jersey thing, since you are going to be going through the London Embassy, you should be safe to compare your timeline & case to other UK cases, there's no part of the process that would be different. If you are still interested in finding more cases like yours, you could also look for beneficiaries who are from Guernsey or Isle of Man, which operate the same as Jersey.
As far as the adoption thing, in the UK you actually don't need paperwork to change your name. You can change your name by "usage", so as long as that's the name he has used, that's his name. So even if the adoption paperwork is questionable, it shouldn't be impactful.