Sentence 1. means that there is one husband with plural widows (which might be possible), but one husband probably wouldn't have 'pyres' (unless they were burning his body and one widow on one of them and his belongings and another widow on another. This is not a likely explanation.
Sentence 2. means that there are plural husbands with plural widows (maybe one each, maybe plural each). Each husband probably has one pyre on which his body and widow(s) are being burned. This is a more likely explanation.
I would need more context to be certain, but 2. is by far the better choice for me.