The Sifsei Chayim explains the first example you gave. I don’t have the Seifer on me, and even if I did, I would probably not be able to do justice to his explanation. But basically, he says something to the effect that everything that happens to a person is from Hashem even when it comes about through someone else. However, when something happens through someone else, it is MUCH harder to have bitachon that it is from Hashem. Therefore, it would be harder for Yosef to have bitachon that it is from Hashem if it came about through people. Since he would have less bitachon, he would be zoche to less hashgacha pratis and more likely to come to harm.
The basic idea is that everything is from Hashem, but when it comes about through others, it is more challenging to have bitachon that it is really from Hashem.