Player A attempts throw-in after made basket, she steps on floor then steps back to attempt throw-in. In this case, not a spot throw-in when does the violation occur? Can she step on the court then back and attempt throw within the 5 seconds allowed?

If she had both feet out and possession of the ball at the same time, and then stepped inbounds however briefly, that's the violation right there. If in the process of rounding up the ball, she started to go oob and was bobbling the ball, stepped in to get the ball and then stepped back and threw it in, I've got nothing.

Sheez, 3 "Inbounds after a Made Basket" questions in one day. What was on TV last night?!?

Since there is no designated spot to leave in this case, the player could also put the ball down on the floor out of bounds, then run onto the court, and finally return pick up the ball and make a throw-in. Of course, the 5 second limit still applies.