all 3 of those are completeable(except 2 bosses in ulduar: Hodir and Yogg), either you skipped a boss or you're doing it on the wrong difficulity (it's your fuck up either way)
Actual problem with raids is if whole group leaves the instance you can't continue because it doesn't save. (for example if you got 2 people on ICC, both of them die and release, you won't be able to continue). Perhaps that's just on fun realm.