Hi Bob! Welcome to the journey. To answer your first question: Yes, the Waite-Colman deck is the exact same as the Rider-Waite deck (often called Rider-Waite-Smith or RWS to rightly credit the artist, Pamela Colman Smith).
Since your primary interest is Kabbalah, both decks are highly relevant, but Aleister Crowley's Thoth deck is explicitly and deeply coded with Hermetic Qabalah, Hebrew letters, and the Tree of Life pathways. The RWS has these elements too, but they are more hidden behind pictorial scenes.
As for buying new vs. used, it's a personal preference. If you buy a used or mass-produced deck, you can make it 'yours' simply by cleansing it (passing it through sage smoke, leaving it under moonlight, or just sleeping with it under your pillow to bond with its energy).
It's wonderful that you are using Tarot for structural life-mapping rather than just fortune-telling. Many people do the exact same thing when trying to map out their paths or find your love through personal destiny matrix chart studies, which also bridges the 22 Major Arcana with personal birth grids to understand life lessons and spiritual blueprints.
