Breeding a Ditto with it's Normal Ability Limber with a Gligar with it's Hidden Ability Immunity
At the moment the exact percentage has not been announced for a Male or Female Pokémon to pass down it's Hidden Ability to it's offspring when bred with a Ditto. As in Generation V Male Pokémon could not pass down their Hidden Ability to their offspring, and Females could not pass down their Hidden Ability when bred with a Ditto.
Hidden Abilities cannot be passed down from male or genderless Pokémon, and will not be passed down if the female was paired with a Ditto
As of Pokémon X & Y, there is the possibility of passing these Hidden Abilities without the use of a female Pokémon. If you have a male Pokémon with its Hidden Ability, and breed it with a Ditto, the Pokémon has a chance of having its Hidden Ability.
Breeding a Ditto with it's Hidden Ability Imposter with a Gligar with it's Normal Ability Hyper Cutter/Sand Veil
The chance of hatching a Gligar from an Egg with it's Hidden Ability in this situation is 0%. Whether Ditto has it's Hidden Ability or not, Ditto's Ability is irrelevant to the inheritance so to get a Gligar with it's Hidden Ability you need to breed a Gligar/Gliscor with it's Hidden Ability, when breeding with a Ditto.
In Generation VI, any Pokémon, including male and genderless Pokémon, can pass down their Hidden Ability when bred with Ditto. Ditto's Ability is irrelevant to inheritance.
Breeding a Ditto with it's Hidden Ability Imposter with a Gligar with it's Hidden Ability Immunity
Well since Ditto's Ability is irrelevant it will be the same chance as the first answer.
I'll update this if I find the answer to the first question has been announced.
Hope I helped :)