How about this, when you get all of your Aunt's stuff sorted out of what belongs to your family, make a detailed inventory of it, including what can and can not be scanned and copies made, and send a copy of the inventory to each of the cousins. Ask them to thrash out who gets what, then you'll copy what can be copied, and send each what they aggreed that they want.
Can these items be sorted as to their importance to a geneologist? Then the documents most import to geneologist would go to cos2, and the rest to cos1, with their approval, of course.
Good luck.
Spotted Pony