You collected courage quickly! very good and informative addition! Now somebody should make Stage IV. I'm completely unaware of details.
You might also want to look at stage 2 and 3 by Vid. The whole trek is 180km long (the ridge is 140km but there are some detours). April might be too early, especiallly in stage 3 which is not sooo easy...
Bivaks - yes can do that but there also are a lot of huts which have winter rooms.