First, let's make sure that your tank is cycled. Get an API Master Test Kit and test your water for ammonia, nitrItes, and nitrAtes. Your readings should be 0ppm ammonia, 0ppm nitrItes, and 10-20ppm nitrAtes. Until your parameters reach the desired levels, do daily 50% water changes with Seachem Prime (it detoxifies ammonia in all its forms, including nitrite).
Once that is taken care of, we can move on to your stocking issues...here's some things to think about while your tank is cycling...
The cories (of which the pictus is not one) will school together, but you might want to get at least one more.
The whiptail cat (aka-whiptail pleco) is okay for your tank, since they get to be about 6".
The pictus will also get to be about 6", but will basically eat anything it can fit into it's mouth, so every fish in your tank other than your whiptail cat is at risk of being eaten once the pictus matures.
I agree with aakaakaak about the penguin tetra. Either fill out the school (to 5 or more) or get rid of it. Tetras do not do well at all on their own. Same thing goes for the danios, except they will become nippy and aggressive when not in a proper school (of 5 or more), while the tetra will just become reclusive.
Now onto the barbs...the tiger barbs and green (tiger) barbs will school together. The rosy barbs *might* as they are similarly-shaped, but I wouldn't count on it. I can't find any reference or pics of a "hexagon barb," so I don't know what to tell you on that one (unless you mean a checkerboard barb?). The gold barbs are more peaceful than the tigers or rosies and won't school with either.
Here's what I would do...I would get rid of the tetra, danios and pictus cat. I'd add one or two more cories (any variety, really, as cories will school regardless of color). I would add at least two more tiger barbs (regular, green or albino...doesn't matter since they'll school together regardless of color). I'd bring your other barb schools up to at least 5 each. The whiptail cat can stay.