You say never Trumper as if that's a bad thing. Unless Trump changes pretty radically, and at this point it's looking like that would require a brain and personality transplant, the Republican party will be glad moving forward to have some people left who openly opposed being led by a childish loud-mouthed bully without discernible conservative philosophy like Trump. Of course there's plenty of Republican politicians who don't actually follow him in any meaningful way, but it's easier to get credit for principled and public opposition than for 'I tried to limit the damage without rocking the boat too much'.
Maybe. Depends who's appointed to replace him. The best case scenario here is that somehow, against all appearances, the firing was not about the Russia investigation or Comey's denial of Trump's claims. That it was in fact done for valid reasons, and the only thing that went wrong was Trump and his staff lacking the political sense to see beforehand what this would look like. I'm generally in favour of the 'don't ascribe to malice what can adequately be explained by incompetence' idea, so I try to keep an open mind on that possibility. But hell yes, I'm sceptical.
You mean the same way that Trump and his staff in the White House make horrendously bad showings on a weekly basis? And he loves it as long as the bad showing involves polishing his ego in public? This would be a credible argument if used by a serious president, but when used in defense of Trump it's almost as laughable as the arguments he actually did use in the letter he sent. Which, incidentally, I see you're smart enough to avoid mentioning.
If you're frustrated that everyone is harping on Trump's every move, you may want to consider that this has something to do with the man himself and his track record so far, both as a candidate and as a president, which is to say negligible on accomplishments while redefining all previous standards on blunders and controversies. He won't be due the deference presidents would normally be due until he can act like one.