Forced ability modifier on Natural attacks

Hello good people, I am building some Dragonborn Subraces and ran into a small snag. When making their breath weapon attacks, I am required to link an ability, which then adds that score modifier to their breath weapon, which RAW says that the breath attack of a dragonborn does not have this bonus to damage. The "?" nest to the thing says "if applicable", but is still required to fill in order to save changes. Any tips on how to fix this?

Secondly, one of the subspecies gets a choice when they use their breath weapon of a line of scalding water or a cone of thunderous sound. Atm, they are listed as two separate breath weapon attacks, each with a number of charges equal to proficiency, instead of two options under one breath weapon classification, and I do not see a way to combine them into one count down of uses with separate options. Any tips for that would be greatly appreciated. 

Thanks in advance!!