309/100 Visa Sponsorship if Sponsor Not Working

Hi All,
Hope somebody could shed some light on this. I currently hold a SC189 visa and its due to expire in 2021.
I have activated the visa but is yet to move to Australia. Planning to do so on 2020 after winding up some commitments. When I got my PR i was not married, I recently married and was looking at options to bring my husband to Aus when we shift there in 2020. The 309/100 pathway looks straightforward except for the sponsorship.
1) Would my husband be able to apply for this visa when I the sponsor is currently residing outside Australia with him, I'm currently not working either as I quit my job to move with him after marriage and not sure when I will take up employment ?

2) Do I have to move to Australia in 2020 by myself and subsequently get my husband to file the 309/100 application?

3) Since I do not have a job now and will not have a job straightaway in Australia when I move there in 2020, where does that leave me as a sponsor, I have my brother in Australia and can he provide an Assurance of Support for my husband to apply for spouse visa to join me in Australia?

4) Is there any possibility of applying for partner visa when both the sponsor and applicant are currently residing outside Australia?

Any help or advice would be much appreciated.