***** NOT A TEACHER *****
Hello, Mawes:
1. I tend to agree with you that "to comment" and "to waste" are infinitives that modify the nouns ("confidence" and "time," respectively).
*****
2, You say that "walking down the street" in "The guy walking down the street" is an objective complement.
a. Of course, your humble servant does not know enough to say that you are wrong.
b. But do consider a few points.
i. "Objective complement" refers to a word or phrase that completes the object.
a. Thus, perhaps we can say that in "The guy robbed a girl walking down the street," the words "walking down the street" are an objective complement, for they complete the meaning of the object ("a girl").
ii. But in "The guy walking down the street robbed a girl," isn't "the guy" classified as the subject? Just a few ideas (not "answers") for you to consider.