Some type 'F's were fitted with induction-coil buzzers ('Buzzer, T Mk:1'); others weren't. Buzzers are interchangable with the ordinary coil (both mounted on a withdrawable frame), so you might come across some, somewhere.
Agree with Phil about testing the magneto - should produce about 90V AC RMS! Fingers are good for testing.
Type 'F's were not used in the 'front line', being more robust versions of a desk telephone with a gravity-operated cradle switch. They could be connected either directly to each other, or to a field-exchange. I would guess they would work about five miles apart with good batteries.
9V should be OK, and you're unlikely to fry the mics on the current produced by same. I use 4.5V batteries on the 'house' telephone system (2 x type 'F's and an Ericsson desk magneto, one leg to earth and the shed link via my long-wire aerial) without any problems.
One other thing: the original rubber-covered wires can go brittle and/or 'gooey', so you might have a duff connection in there. Are the magnetos stiff to turn (indicating a S/C)? When you turn the magneto handle, it should pull a pair of contacts together at the back of the magneto-generator. Are these contacts clean?
Attached is a cct diagram, in case you don't have one. Note that the buzzer version is shown. Yours will be different.
Have a look at my 'Flickr' pics for comparison.
HTH