I know you only need one of the three Forces of Nature and not all three Forces of Nature for the lady to give you the Reveal Glass. This can be found here.
As for whether or not you need one of them with their Hidden Ability for the lady to actually give you the Reveal Glass. No I don't believe this is the case.
The youtube link that I also posted on your previous question can support this in a way.
As even though the player did have one of the Forces of Nature (Landorus) with it's Hidden Ability with him. When he talked to the lady to get the Reveal Glass she responded with the following "Oh! That Pokémon with you! That is Thundurus of legend! Then take this, won't you?" and then she gives him the Reveal Glass.
His Thundurus is Not the Dream Radar Thundurus and Does Not have it's Hidden Ability. His Thundurus is Shiny but it has it's Normal Ability therefore because the lady gives him the Reveal Glass because of Thundurus being in the party I can confirm that you don't need their Hidden Abilities to get the Reveal Glass.
If you did need their Hidden Abilities to get the Reveal Glass, many players would probably be upset because they might not have the Dream Radar's Landorus, Thundurus and Tornadus due to not having Black or White 2. Therefore they wouldn't be able to change their Normal Landorus, Thundurus and Tornadus forms.
Hope this helped, even if it's only in a small way :)
