Theoretically all these problems exist for designers (us), but for user I doubt if all these exist. At any given time, as a user I have few set of tasks to do, lets say 1) I’m in the instagram, I usually copy paste a set of hashtags for certain posts of mine, I know I have widgets in the notification centre, I swipe down and access widgets. I close…
This is a good iteration over the initial idea.
And for multiple matched words, as in case 2, I think it may be better to highlight all the matched words and wait for the user to tap on one of them, since he/she may not have paid attention to the quick flashing words and missed which ones were tappable.