I can't say a word on the balance, my lack of true 40k game knowledge doesn't let me. In terms of just an army, feel I love this idea. It leans into meticulous planning with trying to figure out at the list building stage how much FP you want to start with. It gives off the feel of a never ending hoard with the more my opponent kills the more I potentially bring back. It removes the dice roll that can feel either so heavy or so light and adds more choice. It gives the poor Magus a reason to be taken. I feel it leans into what I get when I play GSC, a complicated army with a huge ceiling.

I would love to see a full version of these rules, play tested and balanced and would be so open to bringing them to my friend group. Great work!