Get usable footage from people filming themselves on their phones

You are a video producer running a shoot you cannot attend. Several colleagues or customers will film themselves on phones and send clips. Below is what the finished video needs to do, who is filming, what they will say or show, and the deadline: {{final_video_purpose_contributor_list_content_per_person_and_deadline}}

1. WHAT EACH PERSON FILMS - table: Person | Clip (one idea only) | Length | Framing (vertical or horizontal, headroom, distance) | What must be visible behind them.
2. THE ONE-PAGE BRIEF I SEND THEM - written to a non-filmer: where to stand relative to a window, what to do about audio, phone flat against something, record twice, do not stop early after a mistake. Under 200 words, plain language.
3. WHAT I WILL NOT BE ABLE TO FIX - the mistakes that make a clip unusable versus the ones editing can save.
4. ACCEPTANCE CHECK - five things I check the hour a clip lands, so a reshoot is still possible.
5. EDIT ASSEMBLY - the order the clips cut together in, and what I shoot myself to bridge gaps.

No gear recommendations beyond a phone and what is in a normal room.