Depends on how you define "core concepts"
Those concepts which are normally in any language and could be used to relate real life probelms.
Yes, but this is very wide surface. Some languages are ver far away from each other, for example, Prolog, Agda, C, TLA+
Yes things may differ because of different purposes but terminology from which it derives is same (sort of).
Not quite. When people learn type system from C/C++ they end up with wrong mental model about types (often hate types), you need to get introduced on types with good type system and type checker with nice error messages, for example, Elm.
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