Do humans actually exist or are we part of the imagination of some greater being? Do we imagine each other?

Do humans actually exist or are we part of the imagination of some greater being? Do we imagine each other?
If there is a great power capable of producing all things within its own 'mind,' and if this is indeed the nature of the universe, then this would be the only 'reality' in 'existence'. The world would be 'mind stuff,' this would of necessity include humans. However, it seems that this great power would have to impose laws on such a creation, 'natural laws' we might call them. Human minds would be individual minds within the great universal mind. Controlled by the laws, all humans would seemingly be guided into a general recognition of things in the way the great power required. Thus, if it was required that all humans should recognise, or believe in, a material existence, then so be it. Each human would recognise other humans, and would come to understand what was meant by 'life' and 'independence,' we would all 'exist' within this 'reality.' As we would all be products of this super power, then such a power could impose anything it chose on the world, including 'free will' for humans: or, if it wished to keep control then our lives would be 'determined.'
