Here are some of my observations & suggestions.
If you want to know how to safely use this soap, perhaps you need to do a
zap test to make sure it is not lye heavy. (Click the purple link.) I doubt that it is, if all your weighing was accurate.
As far as using them for embeds, your impatience is probably your enemy when it comes to cutting them into shapes. You say they are now cut bars, but still too soft. So it's still too soon to cut with plastic cookie cutters. You could, but if you do it while still too soft, the shapes will not hold up around the edges. WAIT patiently. I know patience may be elusive, but it will reward you.
Find something else to do in the meantime. Search the forum for how people manage to get very white soap. That can take some time for sure (the searching and the reading.) Or play around with
Soapmaking Recipe Builder & Lye Calculator designing your own recipes and make a small trial batch of soap.
Once your bars are no longer too soft, test cut ONLY ONE BAR with your chosen plastic cookie cutter (or STAINLESS STEEL, but not any other metal cutter) and see how it goes with JUST ONE BAR. If it is still too soft, leave the rest of the bars our to the air and wait some more.
Once your embeds are cut, then you can decide how to store them. If they are firm enough that you can stack them without damaging them, by all means, stack away. But if you do choose to freeze them, be prepared for another patience waiting game once they come out of the freezer. You will have to leave them alone, UNTOUCHED for a good length of time before they can be handled again. AND if you try to take the pieces apart rather than leave them all in the stack as a COLUMN EMBED, you will likely damage them.
So, what I would do is decide now if they are going to be a Column embed (a column of hearts, or whatever shape you choose) or individual embeds. If you want them to be individual embeds, then I would suggest you place a piece of plastic wrap between each cut shape when stacking them together. Then when you are ready to use them in your new soap, just take apart using the edge of the plastic wrap to pull them off each other.
Instead of freezing, once they are cut and stacked, you can just wrap the entire stack of embeds in air-tight plastic wrap and store in a container to prevent them being knocked about. That will stop them drying out too much prior to being used as embeds, but curing will continue (a bit more slowly, but it will continue.) You will want to use the embeds within a reasonable amount of time of course, not keep them stored this way indefinitely, but I have had no trouble storing soap for later use in other projects in this fashion.
Make sure to lightly wet the outer surface of the embeds when you do use them if you wait a long time, just to facilitate a good adhesion between old and new soap.