How to handle 1-on-1 "morale" conversation

My manager recently had her annual performance review, and one component of this was an anonymous survey in which all her direct reports (40+ people) shared their views on her leadership, etc. I suspect it did not go well, based on the notes she began posting to the shared message board a few weeks later.

One was her admitting that she had come around to our way of thinking on a topic that many people were passionate about (I suspect people really vented their opinions!).

Another was her beginning to encourage us to publicly recognize outstanding colleagues (I suspect this is to help improve morale?)

And the third message called out directly that the performance review indicated sinking morale. She wrote that she would be scheduling 1-on-1 meetings with us (not specific if it was ALL of us or just a chosen few) to gather ideas for how to improve morale.

This last one raised some red flags for me. There has been a lot of voluntary turnover lately (folks leaving long before retirement, sometimes abruptly). I can't say with any certainty whether there is any history of retaliation, but as one of the longer-standing reports to this manager, how do I handle this meeting? Do I...

1. Politely decline the meeting, as it's not technically required? Sounds risky.
2. Accept the meeting, but avoid saying anything substantial that could be interpreted as finding fault with her?
3. Honestly say why I think the morale is sinking (a failure in leadership).

This may be a chance to improve things, so I would view it as an opportunity.

1. Accept the meeting. Declining would signal that you don't take this seriously, which apparently your boss does.
2. Prepare: Think about what are the things that are not working well and what are the things you would change if it were up to you.
3. Formulate it properly. Focus primarily on actionable feedback: on things that could be changed and suggestion on how to change them. Avoid blaming, bad-talking other people and wishy-washy or unspecific feedback. Instead of saying "failure of leadership", make actual suggestions what the leadership could be doing differently.
4. The ideal sequence here is "state the problem" (without blaming), "describe how the problem affects your work" and "make a suggestion to fix the problem"
5. Rehearse a bit. Make sure you can say the things you have prepared properly and with confidence.
6. Set the tone to be friendly and constructive. There is nothing wrong with buttering your boss up a bit and being cooperative. "thanks for having this meeting. I'm glad that you've decided to work on improving our work environment and I'm happy to help, if I can".

Keep in mind that this isn't easy for your boss either. Receiving 360 feedback can be difficult and it appears that they have taken it to heart acting on it. If your boss can make a good faith effort, so can you.