Is my pH too high for all of the following?
Kubotai rasbora
Sparkling gourami
CPD
Maculata Rasbora
Except for the CPD, technically yes. But the GH is the more important parameter, though that is not to say the pH doesn't matter. If I were you, I would see if they are adding anything to the water, or if this is natural.
The water in the CPD (I take this to be Celestial Pearl Danio, species
Danio margaritatus) habitat is slightly basic with a pH of 7.3 but is very soft. I don't see a problem here, but I would point out that this species is best kept on its own in a large group, say 20-30, in a standard 29g or a long 20g (base dimensions of both being 45cm by 30 cm (30 by 12 inches). In larger aquaria, other small peaceful and quiet species will work; active fish can impede the CPD's feeding.
In its habitat, the pygmy sparkling gourami (
Trichopsis pumila) is frequently found in water having no hardness and a pH of 3-4.
The dwarf rasbora,
Boraras maculatus, inhabits black water streams and rivers associated with ancient forest
peat swamps. The water is stained brown due to the release of tannins and other chemicals released by decomposing
organic matter and the
substrate scattered with fallen leaves, twigs and branches. Such environments characteristically contain very soft (negligible hardness),
acidic (
pH as low as 4.0) water and are often dimly-lit due to the forest canopy above. [taken from Seriously Fish]
There is some adaptability in some species, but this is too often exaggerated. The smaller the fish, the higher the metabolic rate and this gets impacted by adverse water parameters (and most everything else). Fish must maintain the pH of their blood equal to that of the water in which they live. A species designed to function in a pH of 3 to 4 is going to find pH 8 or close to it quite a strain. Each degree in the pH scale which is logarithmic represents a 10-fold increase/decrease. So pH 5 is ten times less acidic that pH 4, while pH 6 is 100 times less acidic, and pH 7 is 1000 times less acidic.