1. We played and my gf got a quest that she should discard two followers. He had Unicorn allready and after few rounds she got Cursed by the hag card. Does the hag count as follower in this instance and she could discard it + unicorn ad quest would be complete? Or would she have to follow the exact wording in the card which suggest she should discard all her followers (Unicorn) and after that would have to get rid of the hag before getting new followers?

2. When playing Warlock Quest's ending my gf had completed 3 of her 4 quests when she got the false Grail from the Adventure deck. So she discarded her quest which she hadn't completed yet, does she have to discard completed quest's also, meaning that she must again complete four quests to be able to go to Crown of Command after getting rid of the False Grail.

1.You may use the hag to discard towards the 2 followers.

2. You can keep all your completed quests towards the 4 for the warlocks quest. This was discussed here:http://community.fantasyflightgames.com/index.php?showtopic=22434#253012

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1. We played and my gf got a quest that she should discard two followers. He had Unicorn allready and after few rounds she got Cursed by the hag card. Does the hag count as follower in this instance and she could discard it + unicorn ad quest would be complete? Or would she have to follow the exact wording in the card which suggest she should discard all her followers (Unicorn) and after that would have to get rid of the hag before getting new followers?

Cursed by a Hag is a Follower and counts as a Follower for all purposes, including discarding her to complete a Warlock Quest. Unfortunately, it's impossible to have the Hag and another Follower at the same time. You have to take the Hag as a Follower and discard the Unicorn immediately, so there's no timeframe when you have both and could complete the Quest.

2. When playing Warlock Quest's ending my gf had completed 3 of her 4 quests when she got the false Grail from the Adventure deck. So she discarded her quest which she hadn't completed yet, does she have to discard completed quest's also, meaning that she must again complete four quests to be able to go to Crown of Command after getting rid of the False Grail.

No, completed Quests are only considered as a reminder and cannot be discarded. This was clarified by the last FAQ.