I was able to work it out with NVDA. If anyone here is a fan of Chrome Extensions and is struggling with this same problem, I had success with NVDA+NumPad Minus to get the focus on the right overlay and then using NVDA+NumPad2 to position the Review Cursor on the appropriate button, NVDA+NumPad slash to fetch the mouse cursor and then NumPad slash to left click. Works like a charm for adding and removing extensions.
