I have a better idea after I was surprised about the Y part of
position allowing 0 without causing grabbed entities to drop on the ground before slamming. But I'm using v3 6391 which works completely fine, better than some previous versions I used which resulted them to drop before being thrown or grabbed.
About binding targets, this is where to start binding. Go to the Bindings tab. You can checkmark the box of Show Entity label before or after you choose a model from Entity Model. In that selected box of Entity Model, you see a given list of models from models.txt, which you can choose from. You choose which model you're going to bind as an idea. Select its animation and see which animation has for the falling part. (Mine is fall7.) In binding settings, toggle the green plus box to enable its settings. Then position it to wherever you think that model's gonna be bound. After finding certain values you want, you type in the given values of the position you are going to use, like,
@cmd position 0 -39 0 0 1 in your code. This is how position is set like.
position {frame} {x} {y} {z} {direction/facing}
You change frame from a given animation of the model. Move its position anywhere you want. Plus, you can change its facing/direction. Its facing value is like forcedirection here.
View attachment 10105
In case you're confused about the enemy's offset position in the bindings, just look at its offset here.
View attachment 10106
This is where the entity's animation with offset comes from, and you look at the cross/square offset too if it's checkmarked.