Quests

Just came back from a long break and wanted to work on quests that I have neglected when I first started. Problem is that I don't have enough ship slots and I don't know what to keep and what to scrap. Any help will be appreciated.

What is requirement for Hinamatsuri attack quest, because In my quest list only appears Hishimochi exchange quest.

How is this mission completed? I have already scrapped 2 14cm naval guns. Of course I have everything that the mission requires and no, I don't have the equipment blocked.

First I scrapped 1 by 1 and it didn't count for the mission, then I scrapped 2 at the same time and it got to 50%, I thought "well it looks like I already saw how it is" but I scrapped 2 again at the same time and it didn't count... so what am I doing wrong?