I am not a big fan of little houses and castels in the scape, but it could be fun. Also, I think eventually you will ditch the watersprite, but for a new tank it is a great plant.
I took a look at those manzanita trees, and I am sure they are polyurethaned, in because they are I would NOT recommend you put them in your tank.
Contact Rich O'brien over there and let him know you want something similar looking to those threes, and he will save some raw branches for you that look like those without any coatings or additives. Be sure to soak them for about 2-3 weeks and chance the water every day, and before you put them in your tank, scrub with a scotchbright pad and rinse well, then place it in the substrate to make your "trees"