Yeah I agree with the bag method. You could PM everyone a number and then write down their username next to the number you gave. Then throw those pieces of paper into a bag/hat and draw one out. That way you know the number and username with that number. Or maybe just do usernames... Ignore numbers. You might want to keep a second list so you know who entered though
Feel free to message me any questions, I'll try to help the best I can!
Rummy- Mini Rex Rabbit
Diz jr- Betta
Yoshi- Crested Gecko