This is great, Mark. I have a simpler 3 question version of this at the initial proposal stage which is deliberately short and sweet to keep them engaged:
1. What is your primary objective?
2. Give me 5-10 vanity search terms/things you think people search for when looking for a business like yours.
3. Who are your main competitors and/or sites you aspire to?
I use this at the start to set expectations before investing a lot of time in proposals. The answers to these questions generally give me a good sense of the type of client they're likely to be, and where I can set my own expectations in terms of budget etc.