How do I set it up so that "You know the - cantrip. Starting at 3rd level you can cast the - spell with this trait. Starting at 5th level you can cast the - spell. Once you cast - or - with this trait, you can't cast that spell again without taking a long rest. You can also cast either of those spells with any spell slots you have of the appropriate level. - is your spell casting ability for these spells when you cast them with this trait."
Additionally is there any way to allow the player to choose the ability score for the spell casting ability?
How do I set it up so that "You know the - cantrip. Starting at 3rd level you can cast the - spell with this trait. Starting at 5th level you can cast the - spell. Once you cast - or - with this trait, you can't cast that spell again without taking a long rest. You can also cast either of those spells with any spell slots you have of the appropriate level. - is your spell casting ability for these spells when you cast them with this trait."
Additionally is there any way to allow the player to choose the ability score for the spell casting ability?
Please see the Homebrew Subclasses & Species FAQ #s 17, 1, and 14 in that order: (https://www.dndbeyond.com/forums/dungeons-dragons-discussion/homebrew-house-rules/131411-a-homebrewers-how-to-faq). That will instruct you on how to set up the choice of spellcasting ability by means of Options, and add the spells to each Option.
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