Well, a 75-80 gallon filter doesn't really change anything other than the cleanliness of the water.
If you wait, the Congos will each reach 3 inches, and the pearl gouramis reach 5 inches.
The black tetras should get to 2 inches. If you wait, your tank will start to fill out without you adding any more fish. The synos will get to about 10 inches.
EVEN if you use the 1gallon per inch of fish rule:
6 congos x 3" each = 18
6 Black tetras x 2" each = 12
3 Dwarf Rainbowfish x 2.5" each = 7.5
2 Pearl Gouramis x 4.5" = 9
Synos (angelicus) x 10" each = 20
SAE x 6" each = 12
Golden barb x 3" = 3
= 81.5"
And we all know we're not to follow that rule.
It's safe to say you're fully, even, overstocked.