Best resistors for use in phono stage?

What passes through the loading resister goes to ground.  The signal going to the rest of the phono stage does not pass through this resistor.

Incorrect. Ground is a reference to the Earth Safety. Zero Volts Audio (0vA) is the signal reference. 0vA may not be Earth referenced.

The current is equal in all parts of a circuit. Basic Ohm's Law.

If one sets the reference to the audio signal line, 0vA will show the inverse signal.

This is a good discussion.  

Some have mentioned a favorite for tube equipment. My phono stage is SS, my amps are tube, if that matters.

Vishay Z foils aka Texas Components TX2575 highest resolving, transparent I've used, I don't really hear a specific sound quality from these, consider them neutral. Takman carbon film when I'm looking for a bit of warmth. I'd like to try some of the AN in my next project.

Vishays can be stacked if more wattage needed, gets pretty pricey here.

Wattage. What's the importance of this?

For your purpose—cartridge loading, the lowest wattage resistor will be WAY more than you need because very little power is passing through it.  You can use the lowest rated resistor you can find.