No. You can use the Costume Chest to "Call to Wear..." <outfit category> to get all sims on the lot to route to it and change into Costumes, but during an Incognito Party they will only choose the costumes that are already options for that party, which doesn't seem to include these new ones.
You CAN ask sims to change into costumes if you have the romantic relationship level to do so. So for example I had Bella and Morty start an Incognito Party. They both showed up as the Grim Reaper. I had Bella ask Morty to wear a couples costume and they picked different coloured Luchador costumes.