My tanks never stink either but they get cleaned twice a week.
I am more into the moss ball to suck up some of the ammonia since it's only a one gallon tank. I think since it's a lower maintenance plant she should be okay with it right? I'll give her a sheet on betta care and also maybe get her interested in live plants. Maybe even get her into five gallons because a planted 5 gallon cycled tank would be amazing and I know they have the space...might even get my dad into the fish's care more, he LOVES planted tanks.
I'm thinking of going to the store to pick up some plants for my own tanks anyways.