Welcome Mick. As far as the difference between the Bussekin steels, you will probably get 3 different answers with several different justifications for each. Coatings do prevent rust but I tend to use non coated blades (LE) for cooking. I like them all and use a different steel for the occasion at hand. Bottom line, my answer is yes.

I don't doubt any Bussekin blade for defense, but I would not doubt a Tramontina machete, a steel barrel pen or a Springer .45 for that matter so not sure my opinion counts much...

As far as what's for sale when, that's the learning curve. Embrace it and enjoy the company. Welcome to the Yard.