Yes, the equation "question-mark-in-a-box = 2+3" must all be in Nemeth Code (with the general omission symbol, a full cell, used for the question-mark-in-a-box).
Yes, the equation "question-mark-in-a-box = shaded-diamond +1" as well as the equation "shaded-diamond = 4" must be transcribed in Nemeth Code.
Yes, the right-pointing arrow that indicates continuation of a series is best transcribed in Nemeth Code; including the numbers of the series within the Nemeth Code switch indicators necessitated by the arrow is probably the best transcription.
Yes, the pairs of numbers enclosed in square brackets with right-pointing arrows connecting the members of a pair are best all transcribed in Nemeth Code (with the general omission symbol used for the question marks).
Last, but not least, it would be quite acceptable to include the answer choices, which consist of nothing but simple numerals, within the Nemeth Code switch indicators used for the pairs of numbers connected with arrows.
Does that cover most everything and set you up to feel more comfortable moving forward?