Can't help you with a specific answer on the noise but the slow start after the Jeep sits a while has an easy solution. There is a check valve inside the fuel pressure regulator that sits on top of the fuel tank and is plugged into the top of the fuel pump. The check valve's job is to keep fuel pressure in the engine for fast starts, so the fuel doesn't drain back down into the fuel tank instead. When that valve goes bad and starts allowing the fuel to drain out of the engine's fuel rail that the fuel injectors are plugged into, a slow start is the result.
The fuel pressure regulator is only $80 or so and isn't difficult to replace but you do have to drop the fuel tank to get to it. The below pic shows what it looks like from when I swapped mine for the same reason earlier this year.
And a big welcome to WF!