Ann: BOARD UNANIMOUSLY RECOMMEND RE-DOMICILIATION AND US LISTING, page-135

But for redomiciling to be useful, SEA would need to be the acquirer not be acquired.

MRO for example could easily acquire SEA for cash whether ASX listed or not, makes no difference.
MRO could also offer stock and cash to acquire SEA, and again no difference to SEA on ASX (especially if you got to choose the combo you wanted)

Now SEA acquiring a US listed entity is a different story altogether. Can not see any US publicly listed board agreeing to be acquired for $xxxM in SEA.AX stock. Rules out Sundance using its stock as currency in an M&A transaction. Only if they redomicile would they option be available (IMO).