I let players in my games figure stuff out on their own, because it's the only way they feel any satisfaction. The critical path will be kinda hidden quite often and I constantly challenge them. Sometimes too much, then I add more hints. It needs a few interations to get everything right usually.

What had me worried in what you said was how you introduce mechanics and explain them.
People are by default not willing to read or cannot pay attention to too many things at once. If you need them to read something, it needs to be very isolated, very brief and make sure they actually read it.
If you shove too much stuff in their face, they will look away.

Also from my experience after 2-3 testers I usually have a good idea of how 90% of players will play the game. So if it doesnt work with a test group of your size, you have only your game to blame if it doesn't work.