I-864 is about financial support

You can include the whole world in that document if you want to. I-864 is a document (among many others) that you sister will need when she goes to the consulate to get her immigrant visa. I-864 is not an authorization for immigration.

I-130 is the petition form for immigration. On I-130, you cannot put done your sister's family members. Even if you put them done, it won't work. Read I-130 instruction and tell me if her hu*****and can be included as a beneficiary in I-130.