I don’t know how exactly Neteller works regarding bank accounts. But for sure, money held in UK and Isle of man cannot be seized by a US entity.
I think the real problem they have is to transfer funds in USD. To do that they need a US bank, and they don’t have the required conditions to do that at this time.
The DOJ is trying to destroy online gambling and doing it very well. They don’t need to act, or to have anything against anyone. They can even finish loosing cases they initiate. It does not matter if the people charged is arrested or not. At that time they will have destroyed online gambling anyway.