Yes they need at least 6 months validityNo upfront.
We got medical passed back in Nov 2022 because of the 5-year medical exemption.
On tracker, my 3 dependents' medical expiring on Nov 10, 2023
but only myself, medical expiring on Jun 3, 2023. I have no idea why.... and then I am the only one got medical request on May 12, 2023.
Since your medical is expiring, you are being asked for more info