The irregular order of question numbers, repetition of the same numbers 3, 4 and 5, and the lack of 7 and 9 are confusing. I believe these mistakes can be easily avoided just by checking your post before posting. Also, you asked too many questions at once. There seems to be so many grammatical topics you should learn even in just two or three questions.
3)
たいヘんなこと is not the subject.
You missed 出ようと. It expresses the purpose of 立った.
4)
こそ泥 is a single word. The dictionary says it's the abbreviation of こそこそ泥棒.
こそ泥(コソドロ)とは - コトバンク
5)
にさんじかん
2)
みな(=皆)「貝」という字が付いています