I guess I'd better show some examples of use of "入れ替わる".
E:The paintings are changed.
E:He opened the door, and let in fresh air
E:It's still not changeover time
E:"Member of board are replaced."
*This "入れ替わる" can be "異動(いどう)になる"
異動になる/異動させられる mean "to be transferred (to other division, branches)".
異動させる means "to make personnel changes"(subject may be your boss).
I guess your definitions are closer to the word.
When the focus is on the person, "異動" is better
When the focus is on the places, "入れ替わり" is better
When you say "high turnover rate", you can say both "入れ替わりが激(はげ)しい", and "異動が激しい".
By the way, 入れ替わる is an intransitive verb.
Perhaps that makes you confused.