Being upfront from the beginning will behoove both you and the organization. Explain how much you'd like to join the organization and how it aligns with your strengths in lots of way and then share how your qualifications are more in line with an X title and compensation. Outline what else you believe you can bring to the organization and how it will drive savings or revenue to the bottom line so they can see the entire scope of your value.

Following up here that I approached this conversation as a business partner would, and with gratitude, and it went over very well. The manager has promised to look into my thoughts/request, and said he thought it made a lot of sense and understood why I was asking.

Honesty is always the best policy. Since you know what you want and are prepared for the worst which is not moving forward with the role if they cannot accommodate your request, it is only fair that you openly communicate with the company. Do it respectfully, explain your reasons as to why you think you are overqualified and why you are asking them to be flexible with title/level etc. Most organizations have flexibility but might involve further approvals etc so you may not get a response immediately. Good luck .

I think you have to be honest, but explain that you are willing to start in this role as long as there is room for growth. I've come to the realization that you have to advocate for yourself in your career, so you need to let them know you are more capable than the job you are applying for. However, you also want to explain that you are adaptable to change, and love a challenge (if that's accurate). Right now, they may only need to fill the existing role, but that doesn't mean there won't be better opportunities in the future. You want to be careful about how direct your tone is because they may consider you overqualified and not offer you the position. Go about it professionally and honestly, but be confident.

You sound like you're on the right track with your second bullet: "I'd like to understand if there's flexibility in scope/title /level/comp to join this organization in this function." Just fluff it up a bit - tell them how much you enjoyed getting to know them and think the culture is a great fit and explain that your greatest value add and focus for your next career step is xxxxx... as you've learned about the position under consideration, you realize that you are looking for a more senior (scope/title /level/comp), and wanted to raise the issue in the interest of providing the highest level of service toward their goals, objectives, vision. Good luck!