US Immigration Questions

You should apply through as many green card categories as are available to you. The family-based green card can be upgraded once he becomes a US citizen. You will be able to get and keep the green card through whichever category comes through first.

There is no new bill, just a policy clarification. And, yes, she will have to wait per the law.

Theoretically, an I-140 does not require you to be continued to be employed by the petitioning employer. You could leave after applying, but if there is an RFE, the employer would not be motivated to respond to it. As a practical matter, there is a second difficulty as well. Could your intention to continue to work at the employer be called into question because you had a preconceived intention to leave? That does not appear to be a major issue with the USCIS, but you never know.