A G lens like the 50 1.8 G will autofocus and meter fine on an F5, you have nothing to worry about it that regard. The F5 does have a screw drive autofocus motor, indeed one of, if not the best- but it can operate lenses with internal motors just fine as well. The only consequential difference between a G lens and an AF-S lens from the F5's era is that the G lens lacks an aperture ring, which isn't something you'd miss with the F5 anyway, it works better controlling aperture through the dials. Some very recent Nikon lenses have switched to an electronic aperture, which will not work on the F5, so barring a few very recent exceptions, you should be fine with nearly any G lens.