I think "TruImp" will be confusing, since "I" will look like "1" or "l" in many fonts.
My suggestion: Change it to Timpch or Trimpc
2. "will be impeached by the House of Representatives" is satisfactorily precise, and should not be cluttered with extra verbiage such as "Resolution constituting articles" . However, the claim description must explain other details of impeachment, such as that "impeach" means to bring charges, but does not imply conviction. The Clinton-Nixon contrast would be useful.
3. There's no need for a clause for eventualities such as choosing not to take office, resignation, or death, since all of those imply that there will be no subsequent impeachment. However, the claim description should explicitly explain that.
Also, the claim could be judged early if any of those events takes place.
4. As for "the claim probably should not take effect until after Trump is sworn in" = no, that is not necessary, since Trump cannot be impeached if he doesn't take office in the first place. (Again, explain in claim description.)
As for "if that seems ambiguous" - no, it is NOT ambiguous! Impeachment is impeachment. The only ambiguity would be in the mind of a reader who does not sufficiently understand the term "impeachment". That can be taken care of by including sufficient explanation in the claim description.
As for "listing other eventualities would cause people to overthink it" - yes. All the other eventualities should NOT be in the claim statement, but should be explained in the claim description.