My 2 cents :
If you ask me the question "shoud we create a focaliser role" (I make it simpler even if your question was broader), my answer is : nothing can tell you here what solution you "should" pick up. But you can take any initiative that helps you to solve the tension that you feel, which is "the client is not getting info and is at times dissatisfied". So I would suggest : try one of your ideas, propose it in Governance, and see what happens. For example, your "focaliser role". Reminding that in holacracy, we're looking for one possible solution, not the best one (and then we sense and adjust if necessary).
When I read your post, I interpret it like if you have a proposal, and at the same time, an objection "And yet we don’t want this role to be the manager directing how people should work ". Maybe I would invite you to raise this objection to your own proposal, and if I was facilitating that, I would test it and help you to integrate it if required. I don't know sufficiently your situation to imagine what could be a solution, but maybe a bit of coaching about what can / can't do someone in a role, maybe clarifying accountabilities on it, or domain on others. Or maybe you try to help other roles than yours, and can trust they have their own power and freedom to raise objections.
Last advice : stay grounded on the tension, that often helps. If the tension is about "the client need information", maybe as a first step you just need a role to bring together and provide information, not a project manager.
Hope that helps, have a good day !