For low light, the java moss and anubias should definitely work. I think amazon sword should too but I'm not too sure about that since I've never grown it.
For your fixture, see if you see a PAR value for it. That's the one that you can match up against this thread to see if you have low, medium, or high light. https://www.plantedtank.net/forums/sh...d.php?t=160396
I think marinelands usually come in from low to medium par. There's a marineland single and double bright measurement in the thread above but I'm not sure if your 55g led kit qualifies as either of them.
Nonetheless, you'll probably find out in the beginning that it's almost too easy to have too much light so I don't see why you can't use what you have. Most people fall into the trap of getting a high light and then getting tons of algae in their tank and crappy plant growth.
DIY CO2 should help but you'll probably see the most gains if you fertilize in addition. There's macro and micro fertilizers. Most of the fertilizers that you purchase at the pet store will fall under micro fertilizers. I think most pet stores are very unprepared for planted tank setups. There's guys who sell macro fertilizers in the for sale section here. If you're lucky enough to have a local fish store who's got some knowledge of planted tanks, maybe they'll sell some macro fertilizers too.
Those are the answers to the questions you asked, but I'm sure you'll have more questions and probably some you didn't ask so, as you start with this hobby, what you need is this:
Darkblade's Primer to Planted tanks
Also, just to show how little you need to get your tank running, there's a low tech section of these forums that you can peruse where guys are running fish tanks in jars. No co2, no filtration, etc.
As for your DIY canister, it sounds interesting but it seems like a lot of maintenance. Your penguin is a hang on back (HOB) filter if I'm correct, those are one of easiest things to take care of. If you find that you don't want to mess with co2, I personally think that type of filter is one of the simplest to use. Even IF you mess with co2, there's ways to get an HOB going with it, but it gets tricky. The other problem is expense and time to tinker with that DIY canister. You also have to get a good non leaking pump, which can drive your costs up. You may find that adding together all the materials and pump, you can find either a secondhand eheim in the for sale section or a new sunsun canister for roughly the same cost. Other than that, I'll readily admit that it's pretty cool if that's your thing and it should work fine.
And yes, carbon filters are sort of passe now
I think it's because we've figured out that if you're cheap (like me) and end up keeping the carbon over a few months when you should've change it out, the carbon ends up leaching the impurities it sucked up originally back into the water. Filter floss should work fine. Even better is something called poret foam, but it's kind of costly.