We are building an iOS video-editing companion workflow. An iPhone 17 Pro (USB-C) is the editor/master; an iPhone 14 Pro Max (Lightning) displays its continuous frame-by-frame live preview. The companion must follow playback, pause, seeks, and edits. It does not use a local copy of the media. Our prototype captures composed AVPlayer output with AVPlayerItemVideoOutput, encodes H.264 in real time with VideoToolbox, sends samples through an MCSession stream, and renders them with AVSampleBufferDisplayLayer. We want the best public, App Store-compatible transport for high quality, low latency, adaptive resolution, and reliable recovery. Can an ordinary iOS app send arbitrary stream or IP data directly between these two iPhones over a USB-C-to-Lightning cable? If not, is wired Ethernet via supported adapters and a common network the supported wired option? What are the discovery/routing constraints? For wireless peer-to-peer video on current iOS, should we prefer Network framework with Wi-Fi Aware where available, peer-to-peer Wi-Fi, or another transport over MultipeerConnectivity? Can Network framework prefer a wired Ethernet interface and switch paths without losing the editing session? For a live editing preview, which transport and codec patterns keep latency bounded while preserving frame order and recovering promptly after loss or a seek? Are QUIC streams/datagrams appropriate? What receiver feedback should drive bitrate or resolution changes and keyframe requests? Are there public examples or documentation specifically for live video between two iPhones with this USB-C/Lightning pairing? We cannot share the full Xcode project publicly, but can create a minimal reproducible example if needed. We would appreciate guidance based on public APIs and supported hardware paths.