A client who makes a lot of edits is almost never a difficult client. It's a client who wasn't asked the right questions at the start.
1. Who exactly do they sell to
Not "businesses". The industry, the size, the person who signs. As long as that answer is one vague sentence, everything you write will be vague.
2. What won't they say
It's the most valuable question and nobody asks it. Off-limits topics, competitors not to name, positions they'll never take in public.
3. What are their ten reference posts
Picked by them, not by you. Those posts define their voice. The extraction method is the same as for a solo founder: tuning AI to a voice.
4. Which words they never use
A list of don'ts constrains better than a style description. Write them down, and run every deliverable through the generic content detector before sending it.
5. Who approves, and how fast
One name. One deadline. Without that, your calendar will depend on an approval chain you'll discover at the worst possible moment.
6. What's the six-month goal
Hiring, raising, selling a service, preparing an exit: these don't call for the same content. An unspoken goal turns into a complaint three months later.
7. How will we know it's working
Set the metric before you start, not after. If it isn't defined, the client will judge by likes, and you'll lose that argument.
Seven questions, forty minutes. It's the best return on time in the whole engagement.
And the profile
Before you write the first line, look at their page. It will get all the traffic you're about to generate: the profile audit tells you in two minutes whether it's ready for it.