Welcome to the forum! I don't think your gecko will like freeze dried food like that but I suppose it will depend on the species and individual. I don't see the harm in trying. What kind of gecko are you getting? What stuff do you have leftover from the crabs?
Sorry to hear about your loss Aliza :(
I agree with Aliza's assessment here. You've done everything in your power to fix it and now you can refocus your efforts on making her comfortable and giving her peace. <3 I'm sorry - this is one of the hardest things about gecko ownership.