In my game i have offered the optional class features, and no one has needed to create a new character yet but the classes would be available if they needed to
i have not offered the optional race/heritage rules. but this is because if a player when creating the character before these rules existed could justify the reasoning for a change i would have probably have allowed it or found a way to meet halfway. so race/heritage modifying rules will always be for full discussion to make fit the world
in terms of dwarves i see the constitution bonus / poison resistance being from essentially growing a specially cultured beard that acts as a HEPA filter removing airborne poisons and dusts. if a dwarf hadnt grown up in mining caves but more of the city, they might have naturally only gained a +1 to con and a +1 elsewhere.
In the next campaign i run Elves will not be available as a player race, as they are banished to the fey lands due to cultural lore. (with the exception of a slightly modified drow) and half elf's are heavily shunned by the world for their link to full elves.
Vision is dependant on family tree in my games for what might be available, humans if they have a bit of another race somewhere back in the ancestry can roll a d% and possibly gain special vision properties, tieflings can try a d% roll and possibly gain devils sight, the d% roll for vision changes is super low between 2 & 5 % but it gives a chance