This is what I found about the enemies in RAM:

$0505 - $0517 Displays the enemies on screen.
$054D - $055F ?
$0595 - $05BF Enemies Health
$06CD - $06DF Sprite for the enemy ?
$072D - $073F ?
$07A5 - $07B7 ?
$07ED - $07FF Sprite?

I'll look more into this!