The entire reply interaction form for DiscussionTools should probably be in some sort of grouping, to indicate to screenreader users that everything from the toolbar, edit surface, summary, cancel/reply buttons etc belong together, a distinction that is hard identify right now.

Something like role=group (with a label) might suffice for this?
https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/ARIA_Techniques/Using_the_group_role