US Immigration from Ecuador

My sister-in-law works for a non-profit that is a 501(c)3 in the US but operates in Ecuador. We have invited her here to the US and would like to apply for a religious visa exemption. Her purpose in the states would be to volunteer/work at schools and daycares to grow in her knowledge and ultimately be able to better serve the nonprofit. She currently has a 10-year tourist visa. We were told to invite her here for 3-4 months, then apply for the religious visa. The nonprofit would be the sponsoring organization, but since she would be volunteering, she would not technically work here or for the organization. Is this possible? Can anyone provide any guidance/assistance on how best to achieve this? She is also the sister of my wife so we could apply for her green card but she can't wait here while it is processed so we prefer the religious visa.

This is the continuation thread for
https://www.visajourney.com/forums/topic/772877-part-iv-the-big-ir1cr1-dqd-message-group/
which was closed because of its large size.
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Absolutely remember ongoing issues and unfinished conversations from Part IV, and carry on with them here!

There is this question in the DS-260 asking if my father-in-law will be travelling with his spouse. They both have been petitioned but each had an individual I-130 form, so I'm not sure if I should put reply like this

Is your spouse immigrating to the U.S. with you?

no

Is your spouse immigrating to the U.S. at a later date to join you?

yes

Hi,

I have four questions. Please, please bear with me

Context: My sister in law is bringing both her parents to the USA. They have been approved already so she now has to file an affidavit. Therefore, my husband has offered his income/assets if she were to need it (most likely) but we currently live in the same house/address as her.

My following questions are:

1. Does she need to file two different I-864 (one for each parent?)

2. If not, then that means she should only file once and just add either parent as an extra member she'll be sponsoring?

3. In part 5 of I-864, it says "optional" to add a sibling who will submit I-864A but im guessing she should add my hubby in it?

4. Does my husband need to file two separate I-864A or just one and add both parents in it?

Thank you in advance!

Hello! We just got an update on our case and it has been transferred to Vermont from California. Is there any similar situations to us and do you know why this can happen?

Thanks in advance!