As a rogue I'm planning to take Magic Initiate with warlock class. The Magic Initiate feat says:
[...] Your spellcasting ability for these spells depends on the class you chose: Charisma for warlock [...]
- cantrip 1: Booming blade or Green flame blade
- cantrip 2: Minor illusion
- 1st-level spell: Hex
My stats bonuses are: STR : -3 | DEX +6 | INT 0 | WIS +1 | CHA +4 | prof : 4
- Green flame blade :
[...] The second creature takes fire damage equal to your spellcasting modifier. [...]
What is my spellcasting modifier? 0 from INT as rogue or +4 from CHA as warlock?
- Minor illusion :
[...] If a creature uses its action to examine the sound or image, the creature can determine that it is an illusion with a successful Intelligence (Investigation) check against your spell save DC. [...]
What is my spell save DC? 12 (8 + 0 from INT + 4 from prof) or 16 (8 + 4 from CHA + 4 from prof)?