Pet hair works into carpet pile and seat fabric, and a vacuum lifts only what sits on the surface. Odours come from the same source and need extraction, not spray.
This page covers why hair embedded in fabric needs tools beyond a vacuum, how odour treatment works, and how to describe the problem so a quote is accurate.
Hair hooks into the pile of carpets and the weave of cloth seats. Detailers use rubber brushes, compressed air, and extraction to lift it. In a hot, dry cabin the hair also becomes brittle and breaks, which makes it harder still.
Source removal comes first: hair, spills and organic debris. Then extraction of the fabric and mats, then an odour treatment. Masking spray over an untreated source returns within days, especially with the cabin closed in valley heat.
Usually yes, or it moves the job to a higher package. Ask whether pet hair is included before booking, because heavy hair can double the time on an interior detail.
Odour from hair, spills and debris can be removed by extraction and treatment. Odour from mould in a wet carpet, or from a leak, needs the leak fixed first.