Hello and welcome
My first planted tank was a 55g "wannabe-agumi" tank (don't steal my title pls
I had those questions too and the answers will really depend on your budget and the amount of effort you can afford to put into it.
imo, use dirt of some kind. Aquasoil and the whole ADA substrate package if you have cash.
If you want a cheaper alternative, look into mineralized topsoil (mts)
is a start and you can cap mts with whatever looks good to you
There are many other diy substrate recipes, just search around tpt forums
Ime, don't make the substrate too deep, I did that with dirt, peat and floramax, it was very anaerobic, though I will say the plants seemed not to mind.
That being said maybe shoot for 2-3.5 inches total height? I'd say buy 2-3 bags, it may be handy to have a little spare substrate in the future
Hairgrass. (and others) but often.....hairgrass
dwarf hairgrass, eleocharis parvula, is often used for a carpet. It always agrees with a trim ime
Giant hairgrass, eleocharis acicularis, make sure you get this kind if you use it. There is another kind, eleocharis montevidensis. I won't whine about it here, but I will here https://www.plantedtank.net/forums/sh...d.php?t=347130
This stuff will grow out of your tank and some consider it a bog plant
4.) I too am interested in mid ground iwagumi plant suggestions