Hi Mark,
You can do excatly what you described. Your entity would have an attribute for the label/caption and another attribute for the text field. Then you would just associate this entity to whatever entties these note apply too.
Edit: You could a structure similar to this then. The top entity will contain the caption and then child entity will have all the additional remarks. To display this on a page, Pass the single AdditionalField object to a page in a dataview, then use a listview to display Remarks over an association. Then you can just add a new button for the listview.
add another microflow
Hope this helps!