A belated welcome. I enjoyed reading about your experiences
I also have u/g filtration and planted tanks. It took me a few years to be able to grow plants without killing them...............the main reason was that my water temp was too high and the plants basically wilted away. As i love the discus and keep three the water temp needed to be high and like you, I read all about it before beginning. Now with a little experience I have lowered, slowly the water temp and have discus in a planted tank.
As you love the silver dollar, I would advise you go with your love. Make up a silver dollar tank and landscape it to suit them. It could be an awesome tank. I suggest that you have a look at technical thread here and how to build rocks out of polystyrene etc. For varity maybe check out which sort of fish go well with the silver dollars. What fun I look forward to seeing a complete silver dollar enviroment.........if you decide to go that way.
I have tetras in with my discus because they are together in natural state. I also have bristlenose catfish - because they are such hard workers and clean away the algae.
How did the new tank cycle for you??? No problems I trust.