Not all of the following three major gods are the most major and most important gods in ancient Chinese mythology, but will fit in the Zeus-Poseidon-Hades pattern well.
Yu Huang Da Di (Jade Emperor of Heaven)
----------------------------------------
After Pan Gu created the heavens and the earth, he assigned his first son to rule the heavens, he is the Jade Emperor of Heaven
God Power: The Banquet
Much like Thor's Dwarven Mine. You can place this table anywhere on the map. There'll be food on this table from which peasants can gather from. More food if you place it in later ages.
Myth Tech: Hundred Flower Fairies
One or two berry bushes would pop up near the town centre after about half a minute
Kai Long Huang (Sea Dragon King)
--------------------------------
Legendary ruler of the seas who rules from a lavish underwater palace
God Power: Tsunami
A tidal wave pops up and acts as a natural wall. Enemy units which enter the wave would be swept a few screens away and receive a small amount of damage. For buying time in case being rushed
Myth Tech: Blessing of the Seas
Increase gathering rate of fishing boats by about 10%
Yan Wang (Ruler of the underworld)
----------------------------------
Yan Wang, as ruler of 18 levels of the underworld, was a judge for the dead. The dead would be brought before him and judged for his deeds in his life. The worse the sins, the further down the underworld he would be sent. The meritable ones would be reborn as humans or animals.
God Power: Soup of Forgetfulness
All enemy units within a small radius (as small as Great Hunt) turn into Gaia units, ie. belonging to Mother Nature instead of the player. Reduced effect on villagers and no effect on heroes.
Myth Tech: 18th level of Hell
Increase the attack of towers by 1...or 2
OK, below are some candidate minor gods
Huang Di (The Yellow Emperor): Heroic Age
-----------------------------
Pan Gu's second son, sent to govern the earth. But Huang Di had to deal with the forces of Yan Di and another name I cannot translate.
God Power: Feng Shui
Click it on a target gold mine or tree. The gold mine or the bunch of trees would vanish from the map. Can be used to ruin an opponent's economy, during evacuation or prevention of Walking Woods
Myth unit: Qi Lin
Horse with a dragon's head. Has a special headbutt attack which flings opponents, does good crush damage
Myth unit: (name unknown)
Dragon headed turtle. No special attack, does good hack damage.
Myth Tech: Compass Chariot
Increases LOS and speed of cavalry
Hua Shen (Goddess of Flowers): Classical Age
-----------------------------
Pan Gu's daughter. She was assigned the responsibility of planting a hundred type of flowers, which she did and made the heavens a beautiful place. With the help of the the Jade Emperor, she sent one of every type of flower to beautify the earth as well
God Power: Boundary
Named after the Chu/Han boundary in Chinese Chess. There'd be a local 'Ceasefire' in the target area
Myth unit:
Myth tech: Harvest
Peasants food carrying capacity increases
Nu Huo (Creator of humans): Classical Age
--------------------------
After Pan Gu created the heavens and earth, Nu Huo found it a lonely place and created the animals, as well as humans from the yellow soil. She also fixed the mess left by Zhu Rong and Gung Gung.
God Power: Heavenly Army
An army would descend on the target area to help you out, with a timer, kind of like 'Ancestors'. This army would consist of a few infantry + archers in Classical, archers + infantry in Heroic, all 3 types in Mythic Age. When the timer runs out, the army turns into paper and falls to the ground
Myth Unit: Terracotta Warriors
Tough clay warriors with a special charge attack which knocks away all enemy units in its way
Wang Mu (Empress of Heaven): Mythic Age
---------------------------
Jade Emperor's wife. nuff said
God Power: Five Finger Mountain
Walls up the units in a target unit, unfortunately, can trap your own units as well. Like the underworld passage, the barrier can be destroyed but takes time.
Myth unit: Dragon
Flying myth unit which shoots a ray from its mouth like a flying petsuchos. Special attack is grabbing a human unit from the air and throwing back on earth for an instant kill
Myth tech: Forbidden Fruit
Trade caravan carry 10% gold more than they should get for their trip
Gung Gung (God of Water): Heroic Age
------------------------
Brother of Zhu Rong and Nu Huo. Got in a big fight with Zhu Rong and lost, in his escape, he crashed into the pillar of heaven and nearly caused the heavens to fall on earth. The mess had to be cleared by Nu Huo.
God Power: Epidemic
Kind of like Loki's 'Spy', cast it on an enemy unit and he'll suffer Scorpion man like poison. He'll spread it to friendly units adjacent to him. Player would need to delete affected units to stop it spreading. Can be used to weaken an enemy army or distrupt an economy
Myth unit: Black Dog
The hunting dog of Hou Yi who swallowed the moon and caused the eclipse. This is a ranged unit which shoots light balls from its mouth
Zhu Rong (God of Fire): Mythic Age
----------------------
Brother of Gung Gung and Nu Huo. He got in a major fight with Gung Gung and caused major chaos.
God Power: East Wind
A cross between Tornado and Earthquake. Winds sweep into the area and cause big damage to buildings. Units would be thrown away but not damaged. Will affect friendly units, so it's better used with Vision or Spy.
Myth unit: Chinese Vampire
Hopping melee unit. Special attack is similar to the Mummy's. It bites an enemy which turns into a Minion.
Myth tech: Immortality
All human units get extra 20% HP
Phew, that's it for now