Harriet works for an advertising agency as their lead visualizer. it is her job to interpret the client’s creative brief and present it in a visual form. what strategy should harriet adopt for creating the visuals?

Being a member of an ad agency’s creative team, it is the visualizer’s role to know everything about the Client and the Client’s brand --- what are clients looking for in terms of look for their ads, what the brand stands for and what the key message it wants to communicate, the brand’s visual guidelines (e.g. template look to follow, what fonts to use, brand colors, the kind of photography the brand uses, and the likes), what the brand’s ads look like and how their client’s brand’s ads should be differentiated from competition. Taking all of these in consideration, the visualizer can then create an ad that will carry the brand’s unique look and treatment that will make the ad stand out from competition.  

i'm not sure i completely understand your question, but i will do my best.

i think the answer you are looking for is sequence. (see below)

a repeated melodic fragment would be best defined as repetition, while repeated chords (different or the same) could be a chord progression. however, you then mentioned the chord and melodic fragment beginning on higher or lower pitches, in that case, the answer could be best defined as a sequence. the definition of a sequence is as follows: "the restatement of a motif or longer melodic (or harmonic) passage at a higher or lower pitch in the same voice."

let me know if this !