Answering what I can below:
2.) See WYSIWYG Toggle for how to toggle between Markdown and Rich Text editors.
3.) Changing notebook appearance when dragged over may be more helpful. Another option is pressing Ctrl+Shift+P then using moveToFolder to type or select a notebook.
4.) Search plugins like VS-Code Style Note Search show search scope.
5.) The first line of Tools > Options > General shows full path of where notes and settings are stored.
7.) Workarounds include prototyping that with the Slash Commands plugin or using a text expander.