I-864 Questions, need help

[omghz]

I'm a U.S. citizen who married a South Korean that was in the U.S. on a student visa and OPT.

I have questions about a few parts on the I-864

Part 5.
I am sponsoring her so for number 1 I put one.
- For myself I put one
- She is my spouse, but I am sponsoring her, so do I put one again here or leave it blank?

For my joint sponsor, my sister lives with her, but they file taxes separatly and my sister isn't dependent upon my mom.
-Does my mom have to put my sister down in the household size?
My mom makes enough money to support everything, so she doesn't need my sisters income to support my wife.
-If my mom does need to put my sister down in her household size, does she also need to add her to part 6 number 3?

Thanks

And bonus question,
Does my wife have to submit the I-693 again since she's already in the United States?