The thing is...
while your fish might be healthy, you're just not going to see them at their best because you can't really give any of them their preferred conditions.
Let's just look at the first two fish on the OPs stocking list.
The guppies would ideally like;
Moderately hard, slightly alkaline water at about 23°C/74°F (because they come from those waters in Central America)
a fairly shallow tank with a pale-ish sand subsrate with plenty of fine leaved, pale green plants; cabomba perhaps, or Indian fern left to float (because they come from shallow, brightly lit, fairly fast flowing streams; their natural colours are yellows and pale greens and they're surface feeders, so don't care about depth)
maybe a few twig-like branches and a scattering of gravel (because their streams are too fast to have large accumulations of dead wood or leaves; their natural patterns of black markings camouflage them amongst the plants and pebbles, but can also be used for display when they're out in the sandy areas.
The red minor/serpea tetras would ideally like;
soft, slightly acidic water at about 24°C/76°F (because they come from the Amazon basin, where the water is fairly slow moving and full of bogwood and tannins
a dark brownish or black substrate with a lot of bogwood and broad leaved plants with plenty of tannins (their base body colour is dark with reddish highlights, just like wood, and their black markings resemble old leaves)
They're deep bodied and leaf shaped, so want deepish, dimly lit tanks (because they come from warm, slow moving backwaters of the jungle; full of dead leaves and fallen trees)
they want to be in group of at least a dozen, with a mix of males and females (because the live in shoals of hundreds or thousands of individuals in the wild).
I could go through all of your fish like that, but I won't
. Do you see what I mean though? There's more to stocking than just how many fish you can get in. You also want to think about creating a home for your fish that suits them and takes their natural enviroment into account.