Besides spawning a new maniac if none is on the board, the card allows to fully heal a maniac and then move it to any space if he doesn´t possess a sample.

Is this basically a respawn of a maniac anywhere in the mansion? Is this allowed to be done if the maniac is still at full health (i.e. no healing is necessary/possible)?

I would say the answer to both questions is yes.

Yeah, it's essentially a respawn in case your investigators escape the madman or if he's trapped somewhere*.

* basically only fire, because there's nothing else that can trap them, I guess...