Nice to hear you report back here! Glad to read that you've found a house that you all like....however it is twice what you're currently paying. It is going to be a belt-tightening time for everyone.
I would suggest that you call a family meeting with your DDs and lay it all out to them. Then inform your D20 that since she's an adult, you expect her to pay $300 a month in rent and on time which will entail her getting a job in town. No budging on this.
Also you need to inform them of the situation with Smokey and the finances being in limbo. They NEED and MUST understand the whole financial picture.
Back in my high school years, my mother would call a 'family meeting' (very, very infrequently) if she's cross about something (one sister skipping school too often or not holding up on her part with her schoolwork) or some matter that needed to be brought to our attention. We all knew who was in charge and we NEVER ever talked back at her. Not in our DNA.
Can you be that Mom for your DDs? You cannot waffle or cave in to D20. This is the time when the rubber hits the road from here and on.
Glad to read that you've found a house that you all like....however it is twice what you're currently paying. It is going to be a belt-tightening time for everyone.