I can't really help ya out of the new choices you listed, but personally if I wanted to up my stock in your tank I would increase the numbers of my current shoal the bloodifn tetras and serpae tetras, as higher stocking tends to stress fish less when its species specific. And tetras just plain like having there buds with them.
I remember back in the 70's my grandfather had 55g tank, with 55 neons in it. Back then the rule of thumb was one fish per gallon (based on small tetras) not 1" per gallon as it is now. His tank was always clean no water issues and the fish were happy and healthy. But I bet if there was 55 of 6 different small species there would have been allot more stress in that tank. He kept his
pH at about 6.0 via peat filtration, and did weekly peat treated changes of about 10% of his water. And his fish bred like mad, he was forever running 29g baby tanks and giving the suckers away.