The Deep Sea Diver is a 12 inch action figure by Redbox.
Sadly, a red valve is missing from the dive helmet of this example. Just like the GI Joe and Action Man Deep Sea Divers, the Redbox copy was also equipped with tubes enabling him to dive and resurface.
The 8 inch Action Parachutist box is marked M Toy and BBRB, Hong Kong. The actual figure is identical to the one used above and was probably a cheap generic HK doll which was readily available at the time.
The outfit was probably inspired by the GI Joe Fantastic Freefall set. Basic parachute toys, many from Hong Kong, were ever popular with kids. This one being more detailed than most.
The smaller 8 inch Astronaut in the pics is the twin of the one now enjoying new adventures on Moonbase.
I had three originally. One was launched into orbit as part of the eBay Expeditionary Mission some years ago. The other two were put away until now.
The larger Astronaut is also a 12 inch action figure by Redbox, marketed as 'Operation Astronaut'. This version was influenced by Mattel's Major Matt Mason, although other versions, with different designs also were released.