Regarding the inline fuel filter never filling up, there is a widespread misconception that it is significant and representative of some abstract cause. It isn't. In fact, as long as fuel is supplied and there are no leaks that allow fuel to escape or air to enter, it is in and of itself irrelevant. Fuel will wick along and through the filter element with no interruption of supply.
To the matter of the fuel pump(s), there are several approaches that you can take. 1) Retain the in-tank electric pumps, install a fuel return regulator adjusted to a pressure suitable for the carburetor, rewire the fuel pump relay to energize while cranking, reverting to engine oil pressure control once the engine starts, and eliminate the engine mounted fuel pump. 2) Retain the engine mounted fuel pump and replace the in-tank pickups with pre-1987 senders. 3) Retain all of the fuel pumps, add the fuel pressure regulator, and rewire the fuel pump relay control circuit as described in (1).