With 7 people in the company, I would assume that you are close-knit in terms of trust. If that is not the case, then either you need to verify if there is trust or you have verified and there is some missing trust: I think this is underlying reason that you asked the question in the first place. I think this might present an opportunity for you to build trust.

Why I think you should share strategic information with your early employees? In my opinion, not sharing strategic partnerships to early employees misses the point of building trust with your early employees. Your early employees are in it for the experience of ups and down, and they will be benefit from both. Critical feedback from them is especially important at this time.

You will have situations where an employee or even a co-founder leaves, I think you have to be ready for that.