State Department guidance says the principal must enter before or with the family members holding immigrant visas.
Coordinate the sequence before splitting the move
Review the actual travel instructions for the household and do not let a private preference silently reverse the required sequence. Ask about unresolved arrangements before assuming a different plan is acceptable.
The FAQ addresses joining family as a spouse and unmarried children under 21 and directs that they be included in the initial application. Corporate sponsorship of the principal does not automatically include relatives. Vetting precedes any request for the eligible family member's US$1 million gift. Omitting derivative expenses because the principal has a receipt creates a predictable shortfall.
The official program allows qualifying family inclusion with separate charges for each joining spouse or unmarried child under 21. Travel arrangements and immigration readiness run on different timelines, and confirming one does not confirm the other. Booking irrevocable travel for a family member before that person's own documentary approval is actually in hand risks a costly change if that individual's case takes longer than a sibling's or a spouse's. Checking each traveler's documentation status separately, rather than assuming the household will be ready together because planning began together, avoids paying twice for the same itinerary. Where a deposit or non-refundable fare is involved, waiting for written confirmation of that specific person's own approval before committing funds is a more reliable sequence than working backward from a preferred date.