I would not go and purchase moss that isn't very common, example like Christmas moss or star moss. I ordered some of that Christmas moss and showed up months later, completely forgot I ordered it, and it wasn't in very good condition. Plus it never really grew anyways.
If your looking for some type of different moss your better off getting some from your backyard. Which I tried and had good success until I got a bad algae attack and never tried again.
Stick with your plan with the willow, and keep trying different mosses until you find one you like. If your looking for a flatter look go with willow or java, if your looking for something that grows more upright I would suggest some flame moss.
You should add some measurements as well for those sticks, they seem large in the picture for a ten gallon.
Add in about shipping:
Just make sure you get the plants from a reliable source. I received I very bad shipment before when I began to order a lot online and didn't worry too much about reliability and I ended up with just a bunch of stems. Some of the stems grew but most of the shipment was just mush and didn't receive anything for their screw up.