I have escalated your comments and situation to a mortgage specialist who should be in touch shortly. Thank you for taking the comment here and please keep up updated on your progress to closure.
There is a workaround to allow the closing transaction to continue even if the sellers aren't in the country. The sellers can sign a Power of Attorney for the real estate closing, ensuring that someone (who is in the country) can attend to this legal transaction in their stead. [I'm assuming that it was an unforeseen emergency that is causing the sellers to vacate the country and coming perilously close to causing this legal transaction to fall through -- I would be frustrated greatly at the sellers, if this was occurring to me.]
Would it be possible for the sellers and you, the buyers, to draft an amendment to the contract revising the condition to allow the sellers to vacate prior to closing, but acknowledging that they may have some financial liability towards repair/replacement should conditions/contents of the house be altered during the period of vacancy?