1. The FBI does what the FBI does. Same for the DOJ.
HRC emails; GOP voting-right restriction claims. Not in court, not proven, but there were a lot of things best described as quasi-news.
2. You can't. We complained when it looked like Russia was helping Trump (when a more likely alternative is that they simply hated HRC, although these views are nearly mirror images and distinguishing between them experimentally might be difficult).
Nobody complained when foreign leaders said bad things about Trump; that's interference. too, and lacking in any ambiguity.
3. You don't. It's voluntary. If the electorate doesn't impose that test on the candidates, it's still the case that the US government can't.
4. Unless you want to have political parties or the Executive control the press, you don't. It's voluntary.
My take is that the media for the most part found Trump to be buffoonish and they gave him a lot of free PR which they thought would kill his candidacy--in every poll of media folk taken since I've been literature a majority have been (D). Even NPR (hardly Trumpficionados) did this. Now they're engaged in self-flagellating, some finally admitting perhaps they aren't the world and not everybody shared their views. D'oh.
They also go for what's sensational. Hence the HRC's bloodletting, which became less and less as it looked like the race was narrowing.
5. Again, unless you're ready for a government truth-in-media agency a la Venezuela or other countries with a leashed press, you don't. It's up to an educated, enlightened electorate to apply its own wisdom, morals, and principles in evaluating news sources. (And we seen how having partisans decide what's true about themselves and what's true when it comes to their policies and procedures works out.)
Note recent stories that media-savvy millennials suck at distinguishing fake from reasonable news. Low SES folk have the same problem. So a majority of Americans at this point lack the educated, enlightened stance that we think our democracy enjoys. Does that sound elitist? Sure. It should because it is. It's like being elitist by saying that most college-educated people have better literacy skills than high-school drop-outs, or that engineers usually have better math skills than English majors. 0
And the reasonable media play a stupid, foolish game, letting interviewees speak while the listener or reader assumes that they're saying facts and news, but that's another post.