I got all my terra cotta pots at walmart. They have them in the garden area. They have every size, but I got the size that I could put into a 3 gallon glass bowl (which I get from the craft area for less than 3.00), and put one good plant in the middle. It not only works for planting but, you can put them sideways, like the plant is spilling out or, upright. Either way, the females can hide inside and it's safe. There is a big hole in the ones that I bought so, if you get smaller, you might want to plug the hole if it is small. They will get stuck in it and die. I used a piece of moss to plug one of my smaller ones. It's nice and I don't have to worry.
Hornwort will float and also drape down, giving cover. Anacharis (which is thick and only needs a led weight...it will grow roots on it's own), Cabomba plant which is thick, soft and gives lots of cover, Java Moss (just beware that this can also add algae if you don't have a lot of snails or, dont do a lot of water changes), and many more. My sorority for wilds, I call the jungle. I even got some freshwater Mangrove as, they are hardier than bamboo, natural to the habititat and grow big!
Well I got a pot (: an one pretty good size anubia! Should I attach it to the pot (the pot will be on it's side and the anubia would be on the side facing up toward the light) or should I attach it to a rock?
Usually the larger females are alpha so getting similar sized females is best (if possible). Colors are up to you...yellow, red, blue, black, white, orange, green, turquoise, copper, gold, and then all the multi-colored fancy females :)
With deciding on who's most/least aggressive it really can't be decided until they are all in the tank together. Size doesn't really help you determine either, because my girl Lily who is by far the largest girl is at the bottom of the totem pole right now with tattered fins. Also, the girl I pegged to be least aggressive before releasing them is the most aggressive at the moment.
I feel like it is easiest just to release them all together and not worry about least or most aggressive.