Ok, so i stared reading again, even tho not too carefully for a while, so maybe i missed something ...
Anyway its worth mentioning:
Distant spell increases spells with a 5 ft range to 10 ft. All other ranged spells have their range increased by only 50%.
Distant Spell incerases range of all spells ... maybe im wrong here, but i was told by two game masters i know, that is shouldnt work on spells with range "self" ... as for example, Misty Step!
Also ...
Im not sure about either of this ...
But again as far as i (and people i asked) know, neither Fog Cloud or Darkness should work as a spaces of complete invincibility ... they only should cause disadvantage to attack in, out, or within ...
Unless attacker have Devil's Sight invocation ofc, and even that only apply on Darkness.
While in game, they both work as undestroyable barier trough wich no spell, or projectile can get ... im not really sure, since it was long time ago i tryed this ... but i believe i was unable to even attack person who standed BEHIND Darkness or Fog Cloud!