That's not ideal to have Miracle Grow in with the FFOF, but it's not the end of the world. Just consider it a lesson learned. No more Miracle Grow next time, lol.
When I transplant, I pre-make the hole in the new pot with the old pot, or an empty one that's the same size. Then I spray water in the newly formed hole where the new plant will go. Next I sprinkle Mykos all over the hole the transplant is gonna go in.
Next I gently pull out the old root ball and spray it with water, and coat the shit out of it with more Mykos.
Then into the hole, and watered good.
No, to minimal transplant shock.