Acquihire diligence keeps finding the same line item: key engineers whose status depends on the old entity. Here is the route that doesn't stall your integration.
Status tied to a disappearing employer is a countdown; transfers-in-place get legally fussy; and the H-1B backstop answers to a calendar (approximately March 2027) that has nothing to do with your closing date. The individuals most likely to matter to the deal — the founders and principal engineers — are also the most likely to have extraordinary records.
Visa strategy usually starts after signing, which is backwards. Bring the head-count list to a person under NDA-comfortable terms and know which cases are strong before you price the deal.