The second one does look like it might be a female, like my common Pacific garter snake, but I am certainly no expert on sexing them, I only know she is a female because she gave birth to six babies. Ill try to post a picture of her here so that you can try and compare them. If you know they are from the same clutch and one is noticeably bigger than the other, then the larger one probably is a female (although that isn’t certain, since they were housed together, because one might have just stolen all the food). Definitely want to change out the tank stuff, and I second the paper towel idea. Keeping them quarantined from other reptiles is a must as well, you don’t want anyone else infected. Best of luck! I wont be able to get any pictures up until later tomorrow, but I will try to do it ASAP. I’m not exactly an expert, but I hope I can help!