Horwath
Legend
Some spells if not all should be innate/biological.I definitely want background to matter a lot. With everything which is a 'learnt' skill going under there, as well as ASI's. So tools, proficiencies, spells, languages, etc all being under background.
But things like flight, waterbreathing, small size, trance, or breathing fire aren't just cultural things. A bird being able to fly, or a fish being able to swim and breathe underwater aren't problematic.
some skills also.
Almost always elves are describe to have superior senses.
That would be superb described with Proficiency+Expertise in Perception, maybe even Insight.
Athletics plus increased carry capacity(large build) can describe "strong" species without chaining them to mandatory +2 STR.
Dwarven +1 HP per level is excellent way to describe "tough" without spending ASI for +2 CON
Agile species getting Acrobatics and +5 move speed is better that increasing DEX by default.
also as you mentioned, Darkvision, movement modes, resistances, immunities, natural attacks/armor should be genetic.