All you need is some liquid nitrogen, a high quality “seal-a-meal”, and a Sous-vide cooker.
First cultivate a friendly relationship with your local Chic-Fil-Lay manager.
Explain your project and he (or she) will invariably accommodate you if you show up when the place is slow and empty.
Order all your sandwiches dry and disassembled with all sauces on the side.
This works best with the grilled chicken.
Forget freezing the tomato and lettuce, you should have that fresh in your fridge anyways.
While still at the restaurant, immediately put your chicken breasts and buns in ziplock baggies.
Throw the chicken into an ice chest and race home.
Dump some liquid nitrogen into a large bowl and toss in your chicken breasts while still in the ziploc baggies, then after cold and partially frozen seal them in bunches of two. Finish all chicken then give them all another soak in the liquid nitrogen until frozen solid. Quick freezing them like this keeps the ice crystals small and it won’t turn your chicken to mush.
Then put all frozen and sealed chicken in the freezer.
Then do the same with the buns.
Freeze, seal a meal, then freeze solid with the remaining liquid nitrogen.
Quick freeze all your sauce too.
Use the Sous-vide cooker to reheat the chicken and buns in the still sealed seal a meal bags over a period of an hour to two hours.
Cut everything out of the bags and reassemble with fresh lettuce and tomato.
If you follow my directions precisely and don’t skimp on the liquid nitrogen during the initial deep freeze, this should easily stay in suspended animation for a solid year or more at the back of your freezer.