Interesting that in some of those citations, Dan, sutta is in the singular.  That suggests, to me, a genre rather than "texts".  (I'm not on secure ground here;  my Pali grammar is a bit rusty.)

On another topic, my teacher Richard Gombrich also taught me that sutta could be *<sūkta .  But I'd like to note that he wasn't dogmatic about it.  It was represented as a possibility.