The note-taker can (should) be a non-researcher. They don’t even have to leave their desk! They just dial in, take notes, and get back on with their work. If you use a domain expert they can understand all the crazy domain-specific jargon. For example, use a developer to take notes when you’re interviewing a developer.
This might be a bit of an unusual post but due to the nature of this role, User Researchers seem very hard to find these days, I wanted to shout out that I do have an exciting Job Opportunity based in Telford, Shropshire. It's a full-time permanent role, has a very interesting client, the company has a great rep and could offer you career development depending on your own mind set of course.
If you would like to know more, drop me an e-mail with your contact info: firstname.lastname@example.org
I don't think you can know in discovery that your service is going to meet user needs. Isn't part of the point to decide whether to do what you were going to do at all? To that end could this read "Decide what kind of service might be the best way to meet those user needs"?
Choose locations appropriate to users and their user journeys
Remember that the most vulnerable people, also most likely to have lower digital skills and therefore need assisted digital support, are the hardest to find. For someone who has never been online, research needs to be into where their user journey starts, for them, what offline routes it takes until their needs are met. To this end, it is even more important to try and meet these users in places and contexts that they are most comfortable with. Talking to them in a lab with on-screen prototypes to look at, for example, is, to them, jumping to part of a user journey they may never get to. Even if they then say that what they're seeing on-screen is better than they would've expected and is something they would try and use, you're still not finding out what would've happened in the real world when they started the on their journey to meet their user needs.