I can't upgrade the nighting gale armour from flawless to legendary.

nighting gale blade does not upgade at all.

dawnbreaker won't upade from flawess to legendary

silver swords can't be upgraded???????

Some weapons/armor are not governed by a perk. The perks for other weapons/armor make it so that you need a lower smithing skill to increase them from one level to the next, this allows them to get to Legendary by smithing level 100. Weapons that do not have a perk need a level higher than 100, so they get stuck at a lower rank, unless you use an enchantment or potion to increase you smithing enough to bump them up to the next level.