Article II presents a different issue in that the facts are undisputed; the only real question is whether Trump’s partially unsuccessful efforts to impede the impeachment process are a “high crime and misdemeanor.” How does that play out?
You can expect Trump’s attorneys to assert that the executive has the constitutional right to determine whether an impeachment inquiry is legitimate or not, and to refuse to cooperate with a process he considers to be frivolous. Leaving aside the complete absence of any constitutional basis for this argument, it is going to make the GOP senators very uncomfortable, because it will serve as a precedent for future impeachments. If the Republicans decide to investigate, say, President Sanders, what is to prevent him from stonewalling them for the same reasons? It is a conundrum.
I think you are going to hear an argument from the GOP that the underlying charges against Trump were so uniquely flimsy, he was entitled in that particular case to refuse to cooperate without violating the Constitution. No neutral observer is actually going to buy that line of reasoning, however, and a dangerous precedent will have been set.