NICE! Beat out the christmas rush for shipping. Not sure if you have one already but I would get a TDS meter online if you start to notice breeding issues. No real need to get it early if it seems everything is alright.
Just be a bit careful with excel. I've never had problems with it and shrimp, but many people have had shrimp die due to excel usage. However, I dose my excel straight into my flourite, which absorbs it right away. Other people just dump excel into the tank so that might be where the issue comes from. If you need I can recommend you to a guy that sells 9 inch needles + syringes so you can dose excel straight into your substrate as well.
Moss would be a good choice for places where there's low light. Just make sure to secure it so it doesn't clog the filter intake!