It really depends on what your product is, but ultimately you want to learn about their experience using your product (what obstacles they've come up against, what features they use most/get the most value out of, things they don't understand, etc).

You can also calculate an early NPS (net promoter score) by asking how likely they would be to recommend your product to a friend. (http://www.netpromoter.com/why-net-promoter/know)

It'll be tempting to focus in on the areas that are of greatest concern to you (and you can certainly bring those up) but try to stick to open-ended questions to learn the most from your interviews. ex: Instead of "Would you use a new feature that helps you do X?" ask "How do you imagine you'd use a new feature that helps you do X?" or "What new feature would you want us to add?"

Clarity suggest I tell you why I know what I'm talking about before answering your question... so...I have run dozens of these tests from early stage prototypes to global research projects. Here are a few generic tips for you:

Flow:
1. Break the ice
2. Open ended exploration
3. Hypothesis testing

* Avoid using the word "Would" as it generally results in inaccurate responses.
* Reassure them that you want brutal honesty.
* Start by warming them up. Ask them to tell you about the context in which they used your product. That will usually break the ice and get them spilling the beans without realizing it. In other words, "What was going on in your day when you were using this?"
* This weekend, focus on a few key assumptions you want to learn about. Frame a few open ended questions around those.
* "Did this solve any problems for you?"
* "Did you enjoy anything in particular?"
* "Did anything frustrate you?"
* "Would you tell your friends about this? If so, which part? If not, why not?"
* "Was there anything missing?"
* "Any ideas on how to improve this?"
* Then, enter in with some more pointed questions.

Hope that helps!

My first thought was to ask what your product or service was so that I could provide a useful answer, but for now we can stick to the basics and then go deeper a little later.

A big part of my 10 plus years of experience has involved launching new products and services to existing businesses so I hope some of this advice is helpful. A big theme has been the speed of launch, learning and understanding our customers, and pivoting as and where required.

First up, and before asking your questions, take the position of not being completely in love with your offering, as this could hamper your ability to get the most out of your research with your early adopters.

We're very creative in justifying something we're completely attached to even in the face of customers pleading with us that we're wrong. Just be aware of this tendency, as it will save you tons of time.

'Why?' is a good starting point, and is also a really important follow up question. Why do you feel that way? This will lead us to all kinds of places, some of which you may never thought about. The more we learn the better off we'll be in deciding what to do next.

- Why are you using this?
- What problem does it solve? I'll help you rephrase all important question that so that its even more human, and thereby easier to answer.
- If this product or service stopped existing, what would you do?
- What could be better, etc?

Let's try thinking about the fundamentals of your offering rather than the details for now, given that I think this is the first time you're connecting with your 7 odd early adopters?

We're thinking about moving very quickly on the feedback we receive and being flexible enough and open enough to drop big parts of our offering if necessary, because what they want is more important to us that what we'd like our offering to be.

If you want to go a lot deeper in to this feel free to connect. I'd love to hear about it, and help you further.