After the framing, mechanical, electrical and plumbing rough-in, and before insulation and drywall. The walk that sets plate locations happens earlier than that, while the drawings can still absorb a change.

Both. The builder or GC owns the rough-in window and the site schedule, and on new construction the first call usually comes from them. Plate locations, camera positions and where the panel lives come from the owner and the architect.

Yes. The camera position is an architectural decision — sightline, mounting height, which way the light falls at four in the afternoon. The camera itself is a decision you can make later, and a Cat6 run to the corner of the porch works for whatever ends up on it.

Wireless still lands on a wire. Every access point is a cabled run to a specific ceiling or wall, and the difference between coverage that works everywhere and coverage that dies in the primary bath is usually where those runs went.

Conduit and pull strings go out to them while the ground is open and the trenching equipment is already on site. Nothing has to be specified yet for the path to exist.

Same work, different access. Attics, crawlspaces and whatever walls are already coming open do most of it, and what can be reached versus what cannot is the question a walk of the house answers before any of it is scheduled.