I don't think we need anything else. This is already enough for Mueller to bring charges.
It may be 'enough to bring charges', but a competent prosecutor (which Mueller definitely is) will not stop at 'enough.' He will continue the investigation until there is "nothing left" that can be proven. My greatest fear regarding this investigation is that it will get terminated and the reports will be forever buried and/or destroyed. It would not surprise me if someone has already made the calculation that facing a charge of willfully destroying evidence is preferable to whatever that evidence says. Similarly, DJT may decide that the fallout from his own "Saturday Night Massacre" would be preferable to those reports becoming part of the public sphere.
After congress has extracted all of the compliant utility out of trump that they think they can get, they'll dump him. Trump knows this, and must be terrified at how fragile his position is. He's basically Mitch McConnell's little bitch from here on out. He'll do anything and everything to stay in good graces with congress because be knows they can dispose of him at any time for the crimes he has committed.
the GOP is definitely riding DJT as far and as long as they get their wish list. I'm not convinced that Trump undertsands this though. He likely (still) thinks that he's a brilliant person who can fix the nation's problems if only everone would listen to him and stop doing pesky things like following established law and checking his power.
He's also never been one to hold his punches when personally attacked. I remember a magazine article where he talked about his strategy of counter-attacking regardless of the long-term fallout. Something along the lines of:
I'll hit back even if it means we'll both wind up in quicksand. I'll worry about the quicksand later. That's continued to be his strategy as a politician. He's attacked members of his own party who's votes he needed for a legislative "win" - and worried about the consequences later (or not at all). See McCain, Flake, McConnell, Cruz, Corker, Ryan etc.
The GOP will ride DJT to get their tax cuts, then they'll try to drive him to shred the social safety net. Given its legendary status of the "third rail" of politics and Trump's longtime insistance that he will not cut SS I wonder how much traction this will get. I imagine much of his rural base will revolt if told they are privatizing SS like Ryan deeply wants. If we get to this point I predict DJT and the GOP will fracture and the whole thing will grind to a halt.
But congress has other considerations too. It's bad party politics to impeach your president, no matter how guilty he is. They'll want to find a way to soothe the message so they don't lose voters.
This latest crop of GOP has shown little spine. Few spoke up when he ridiculed Cruz's wife, when he mocked a disabled reporter, when he talked about Mexicans being rapists, when he tried to enact two travel bans that were "definitely bans!!!", when he repeatedly called for a former secretary of state to be locked up, when he - repeatedly - pissed off our closest allies, when he attacked the FBI, when he tweeted racist graphics and videos, when he appointed those who had donated to his charity to positions they had no experience in, when he praised dictators and said the US will no longer consider human rights abuses, when he refused to release his taxes, when he again brought up the 'birther' conspiracy he started after he claimed to be the one who ended it, ...
Yeah, they won't vote to impeach him. I think that there's at least a few dozen members who secretly hope they lose the house in '18 or '20 so that the democrats can be the ones to finally start the impeachment process. And/or that Mueller does their dirty work for them by bringing up obstruction and/or collusion charges. They they'll have a giant shield to cower behind when they say "
well it's not me saying this, but given the charges and our laws I simply have no choice". I'm guessing that some of them actually yearn for the days when they were the minority party (or didn't control the WH) when they could grandstand on taxes and healthcare with little fear that they'd actually have to do something and then be held accountable.