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As I said, "If we handled it at all, it would have to be a list, not a category or section, preferably with quotes or other sources to explain when a character was specifically dropped (as opposed to 'just stopped being used or never caught on', which applies to a lot)." This would apply to those you named and many others (especially from those periods in the eighties and nineties when the show tended to add characters in bulk and only a few stuck around).
If you can't find an official reason or quote or statement (just "They stopped appearing after season X"), it's not worth including. (Especially when you'd reach characters who continued to appear in merchandise long after they'd stopped showing up on the show.)