just remember to let your stuff leach out. JUST ENCASE. This can happen while your cycling. your plant ideas are REALLY good, those in particular you can't go wrong with. And the pathos is GREAT specially if your putting it in a little pot. All of them grow well in moderate to low light, no special care needed.
AND no worries about the tank set up, you'll probably change things around again before you settle for what you have. This all happened to me when I first started looking into newts. It's apart of the beginning phase. At least your doing all this before you get your newts! YOU'RE a Smart person!
I'm adding this into your thread, something to think about. If you seal off an area of your tank with Plexiglas and aquarium sealer you can have a land side AND a water side. NOW the Plexiglas glass needs to be tall enough to hold a fair amount of water BUT not so high it's cumbersome for your newts to get over. You've been doing so well with this project I'm sure you can figure this out.
Also if you do this and plant at least three different plants in the water you WON'T NEED a filter, you can just do regular water changes. The plants do EXCELLENT to keep the Nitrate and Nitrite (which is what creates amonia in the end) levels down. Also if you get younger CFB/JFB(Hardier), it'll be a while before they want to get into the water side, in which case you can inhabit that side with GHOST shrimp, which is the only thing I would say is safe to mix with your newts. No fish, no crabs, and NO frogs. lol now once your newts go aquatic, by then you'll probably be ready to move them to a larger aquarium, AND (TRUST ME) you'll be ready for some more babies to move in, which you have your set up ready for them, with a bit of adjustment, I'm sure you can find a way to manipulate the tank for another species.
JUST Something to think about! Also, land isn't so hard to take care of, dirt has a better time breaking done wastes, you can DEFFINATELY plant your pathos in the the land side and it creates a BUNCH of hiding places once it starts creeping about the tank floor.
Here's a link for creating land!
http://www.blackjungle.com/basics.htm
KEEP up the creation! By the end you kinda feel like a God, specially when you first flip on your light and check out all that you did.
I remember, I was so proud when I unveiled it to mom I was like, "and I say LET THERE BE LIGHT! And Sara created the world in three months...." LOL and now I have my shrimp and newt children....
I got my newts from jennewt...