Iirc:
ICOG = 0 to +7.
Miraculous = -7 to +7
Yes, Chaos scrolls give multiple lines, they have a chance to modify every line of existing stats on the equipment.
No, they can give both stat and attack, as long as both lines are present pre-chaos scrolling.
If it makes you feel better, Maple Relay will probably come back in like 4-6months with basically the same rewards. (If the same pattern keeps repeating.)
