Ahead of that date the items will be displayed in a free exhibition at The Cumberland Hotel in London between 23 and 27 September.
The piano, which was also played by Leonard Cohen, Donna Summer and Bryan Ferry, is expected to sell for at least £200,000.
Queen used the piano during the recording of The Game, Hot Space and The Works.
An AKG C414 EB microphone, which can be seen in footage of the band recording the song One Vision, could fetch at least £40,000.
Mack said: “Freddie was not only a colleague and close friend; in many ways, he was part of our family.
“To us, he was never a celebrity; he was ‘Uncle Freddie’ – spending time with his godson Freddie Jr…. and celebrating family birthdays with us.”
He said he hoped a fan would appreciate the items, but added: “The memories we shared can never be auctioned; they will remain with our family forever.”
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