I have mine Cherries and a couple Amano but that is 18G. And love Ramshorn snails. The bright red ones especially and Nerite snail.
Black sand is preferred as they color up better in the darker substrate/ feel safer?!? I have one tank with black and one with white, on the white one I added a graduated blue background and so many plants it now looks like a jungle and the rocks are medium and darker, they look great.
the shrimp also feed off biofilm in your tank so it takes some time to get that developed. If you have a strip of filter pad you could add which had been used for awhile the shrimp would use it to feed off of and love to pick at it. Or you could add a piece into your filter beforehand to start growing BB and stuff to add into your new tank.
I used a piece from a roll of bulk filter to slow down water flow in the HOB return and those guys are up in it all the time picking goodies.
Also what I use to seed for new projects, I would get one ready on an existing tank for your new one and be that much further ahead in your cycle.
I love the shrimp they are fun.
You could go with a ton of options just not the Crystals at first since they need a very established and stable tank with excellent water quality.
Some extra ideas for decor...Driftwood twigs, Moss balls, Java moss, Cholla wood, Anubias Nana, Java Fern, Microsword, Dwarf hairgrass (higher light requirements),