Gradius' Option: Equipping "Axe of Despair" to "Gradius' Option" has no purpose. Activating "Reinforcements" targeting "Gradius' Option" serves no purpose. "Luminous Spark" on the field will not change the ATK/DEF of "Gradius' Option". It always has the same ATK/DEF of the selected "Gradius".

Light and Darkness Dragon: The ATK and DEF lost by “Light and Darkness Dragon” from its second effect is applied to its total ATK, including all other gains and losses of ATK and/or DEF. Example: If you use the second effect of “Light and Darkness Dragon” 4 times (500 X 4 = 2000 loss of ATK and DEF) while “Luminous Spark” is face-up on the Field Spell Card Zone, the “Light and Darkness Dragon” will have 1300 ATK and 0 DEF. If “Luminous Spark” is then removed from the field or negated, the “Light and Darkness Dragon’s” would change to 800 ATK and 400 DEF.

Pole Position: EXAMPLE #1 I have "Pole Position", "Luminous Spark" (+500 to LIGHT), and "Gemini Elf" (1900 ATK / EARTH) face-up on the field. "Gemini Elf" is the monster on the field with the highest ATK, so it is unaffected by Spell Cards. If the opponent Summons "X-Head Cannon" (1800 ATK / LIGHT), "Luminous Spark" will raise the ATK of "X-Head Cannon" to 2300, making it the highest ATK monster on the field, so it's unaffected by Spell Cards, so it drops to 1800 ATK, then increases to 2300, then drops to 1800, etc. This would create an infinite loop. Therefore, the opponent cannot Summon "X-Head Cannon".

Pole Position: EXAMPLE #4 I have "Pole Position", "Blade Knight" (1600 ATK / LIGHT), and "Luminous Spark" (+500 ATK to LIGHT) face-up on the field and 2 cards in my hand. The opponent has "Giant Orc" (2200 ATK / EARTH) face-up on the field, which is the highest-ATK monster on the field. If I Set 1 of the 2 cards in my hand, "Blade Knight" gains +400 ATK with its effect, becomes the highest-ATK monster, and because of "Luminous Spark" an infinite loop is created. So I am not allowed to Set a card.