My wife and I are taking her nephew to HNL next year. I plan to buy his ticket with miles and pay for our two tickets. Obviously we will be on separate PNRs. Once ticketed, I will call and have them linked via TCP as I have read above. Is there anything else I should do or know before proceeding? Thanks.

[Not that it impacts the decision, but I am buying the two tickets to get EQD and EQM towards status. The nephew does not need status so using miles for him.]