In my experience, Velcro can work fine for seats, pegs, etc, but eventually gunks-up with algae, duckweed, grim, etc, and adhesive backing usually fails over time too. 3M's dual lock lasts longer but is harder to acquire and work with.
Methacrylate adhesives, Plexus among them, will attach plastic footpegs tracks to hulls in perpetuity and is available from Johnstown Dist for around $12 for adequate amounts.