The entrance pupil of the Repro-Nikkor 85 mm f/1 is 87 mm in diameter. Hence its f-number, by definition, is f/1.
As the lens is perfectly symmetric, its effective aperture at 1:1 is f/2.
(standard equation) Neff=N*(1+m)
where N=f-number and m=magnification (pupil factor =1 in this case)
It is worth remembering that the pupils are virtual quantities and thus not directly physically linked to the lens measurements. The pupils can be in- or outside the lens assembly.
To your last questions, 'no' is the answer to both. Magnification is already factored into the 'DOF' equation. The entrance pupil is the depiction of the physical aperture (opening), so is a virtual quantity, and acts as the collector of light on behalf of the optical assembly.