You say you have a little bit of moss that could come in direct contact with the frogs correct? Do they hunt there food at all? The male almost looks like he was starved to death which could have meant he got a bit of moss in him and it caused impaction which caused him not to eat.
Its also possible that he wasnt getting enough vitamins. Some frogs dont need it as badly while others require addition of vitamin dust. I never dusted my crickets till I got my Pac (who turned into my Whites...long story) but even now I only dust with calcium and gut load with vitamin enriched cricket food. My Green and my Gray never needed the extra vitamins (been gut loading since I got my Green a few months after the Gray) or the extra calcium and I only started dusting because Pacs are notorious for bone density diseases if they dont get enough calcium. I just went ahead and do it now because, well, it can only help rather then hurt. But I know my co workers say they dust with vitamins every few feedings (not at the same time as the calcium dust) even though they also gut load. I've heard of Greens, Grays, and Whites all becoming ill without vitamin dust supplements even though mine are just fine. Its just a variation in the species.
The last thought I had was stress caused him not to eat. And that may have been something you could not help. Some fogs are high strung (for lack of a better word). That Pac I mentioned, he almost died because he was very very stressed while I had him. I dont entirely know why. His heat, humidity, and enclosure were all set up according to both advice from co workers and people here. He had an eye infection the first week I had him, though, and he spent a week back at the store in there hospital ward and when he came home he seemed fine. But a day or so later he stopped eating no matter what I did. I eventually took him back so they could try and find out what was wrong. It made me feel a little sad because he ended up starting to eat almost immediately upon returning to the store. I dont know why he was so stressed when I had him and to this day no one can tell me why he wouldn't eat for me, its just how it was. He didn't act any different from any other pac man sept he wouldn't eat.
So, like I said, its plausible that it was something you could not help. I would lean more towards the stress option and my second pic would be impaction. Its possible a lack of vitamins but, well, I honestly doubt it. He would have eaten but just looked sickly then passed. Are you feeding them the same thing the original owner fed them? A drastic change in diet could cause stress too.
I hope that long and rambly reply was at least somewhat helpful. I'm so very sorry to hear this happened at all. Its never easy loosing a pet. They become part of your life, your family, and your heart so very quickly that when you loose them it hurts. I hope you can find peace with your little girl. She seems healthy and happy from her pic.