I've discovered a new wrinkle in this process of the young lady legally coming to the U.S.
Use of the K3 could result in problems later on, because the validy of the existing petitions is revoked upon death of the petitoner.
On the other hand, the I-130 is legally converted to an I-360 and her immigrant processing can continue, via USCIS, if a new I-864 sponsor can be found.
About the K-3, the part that I find fuzzy is that the petition, in this case, is NOT revoked upon the death of the petitioner but rather is automatically converted to the I-360 as a matter of law. Although I am assuming she will need to submit a copy of the death certificate to get that done, and I am not sure where she would submit that to.
In regards to the I-864 sponsor, from what I can tell that depends on whether the husband had already submitted an I-864. If he did, then it appears that no new sponsor is required. If he didn't then I think a substitute sponsor would be required, but I am not sure. See the sections I quoted here: http://www.theworldo...i...st&p=219584