Q: I have the skill "Iron Grit" active and a "Gearfried the Iron Knight" in my GY. I activate "Living Fossil" targeting that Gearfried, what happens? A: On resolution of "Living Fossil", "Gearfried the Iron Knight" would be Special Summoned, and "Living Fossil" equipped. Gearfried would start a new chain to destroy "Living Fossil". On resolution of Gearfried, "Living Fossil" would be destroyed. As you now control this Gearfried, and it's unaffected by card effects, it would be unaffected by the Lingering Effect of "Living Fossil" and would remain on the field. When destroyed, it is sent to the GY.

Q: Can a "Gearfried the Iron Knight", under the effects of "Iron Grit", be selected for "Creature Swap?" A: For the effect of "Creature Swap", a player can choose a monster affected by "Iron Grit". In that case, switching control of it with an opponent's monster is impossible, so the effect of "Creature Swap" is not applied.