Acqui-hires work best if you have a relationship with a reliable offshore partner that also has some skin in the game (sweat equity). The natural progression is from small partner to retainer + equity etc
This way you have a way to judge the technical capability and cultural fit. Plus it can only work if the offshore partner commits to sending his employees to sit with yours on rotation (ideally PM or technical offshore liaison). In the longer term the offshore employees should also be contractually bound to join you full time in the event of another round of funding or exit etc.
This makes the offshore team like your own team with restricted stocks units on a vesting cycle (tied to deliverables etc) but at a much lower cost basis
My advice is based on real evidence (a friend of mine was involved in 2 such companies who got sold to Fortune 500 companies) and I've been in your friend's position too as a PM at Amazon and Microsoft. An arms length arrangement and a requirement to scale very fast won't work