You wrote a careful brief and ended with a paragraph of questions. Which vendor. Whether September holds. Can they review the draft. Also, thoughts on the name. They answer the name, because it is easy, and they say they will "come back to the rest." The rest does not come back. You now have a thread that looks alive and a decision that is not.
Seven questions is not thoroughness. It is a refusal to choose what this message is for.
One reply cannot wear two shapes
A decision is a pick. A review is a list of defects. An opinion is a lean. Those replies do not look like each other. Asking for all three in one letter guarantees the cheapest shape wins. The reply mirrors the request. A request with seven mirrors is a kaleidoscope.
Ask for a decision or a review or an opinion. If you need the others, they are later messages, each with enough context to stand alone. That feels like more work. It is less work than a thread you have to re-open twice.
Stacks hide the owner
When you ask one person seven things, you have not decided who owns which outcome. They will take the item that is obviously theirs and leave the item that might be yours. A single ask names the owner by existing: this is the thing I need from you.
If two people must answer two parts, do not CC both on a seven-item letter. Write each of them one question. CC is how you pretend a stack has an owner.
Context is allowed. Extra asks are not.
A briefing can carry the rejected option, the assumption, the brief. Those are not questions. They are the floor the one question stands on. The failure is the closing list that starts with "also."
A useful test: write the reply you want, in one or two sentences. If you cannot, you do not have one question yet. You have a meeting agenda in a mail.
What to do with the leftover questions
Put them in a note to yourself, or in a second draft you do not send yet. If they depend on the first answer, they cannot be asked now without wasting their time. "If you pick B I will ask about staffing" is honest. Asking about staffing and the pick is how you get a staffing essay on option A, which you are about to kill.
Approve a package with one visible ask. If the assistant stacked seven because the session had seven, that is the session leaking. Cut until a tired reader on Monday can see the job in the TL;DR.
One question, one shape, one chance to close. The other six questions will still exist tomorrow. They will be easier once this one has an answer.