I think that you, 12padamas, must be the Montezuma of C2C-LPers. You will just declare war on anybody at any time with no specific plan and without knowing how your military force measures up to the defenders you will be facing... (It is perhaps ironic that your best friend in the game is probably the Aztecs, although it is not Montezuma leading them. That is even after they declared war on you twice, or maybe 3 times, earlier in the game. The turning point in their attitude towards you was when your religion spread to them, and then your going to war vs. the Egyptians has helped as they are at war with them too.)
A lot of your problems come from not being familiar with regular Civ4+BtS. If you were, you would have know what the "join" button on the Hero did. Regular Civ4 does not have hero units, but that effect is normally a Great General ability (which was added for the Warlords expansion). When you use it, you normally do it when only 1 other unit (the target unit for the GG to join) is on the plot since it divides the XP awarded across all units on the plot. In BtS a Great General gives out 20xp, so with just one unit on the plot it gets all 20xp but with 5 units on the plot each would only get 4xp (you had something like 2 koas and 3 healers, for 5 units). Having a GG attached to a unit lets it take some promotions that are not otherwise available (they are generally better than the regular promotions, for example in C2C you can take the Heroic promotion which gives both +20% strength and +20% city attack, or provide bonuses that many unit types can't usually get like +1 move or +20% withdraw). It also allows the unit to keep all of its xp when upgrading (normally the amount you can keep has an upper limit: 10 in BtS or 25 in C2C). Using a hero for this is quite possibly the least useful thing you can do with the hero and I don't even know how many XP they give - however many it is, the benefits from having it attached are not enough to make up for what the other options can do for you (you may have realized this already).
By the way, only 1 healer in a stack is actually useful for healing units. The healing does not combine across units. It just uses the healing amount from the one that will heal the most damage.
Also, once again you moved your galleys (the ones carrying the koas up from Memphis) right next to an enemy canoe instead of killing it (this time it was next to Melbourne). It then proceeded to head for Memphis and pillage the same seafood resource that the Egyptians did last time (although this time you managed to get peace just before they would have pillaged the second one). In this same area of consideration, I think you'll find that the closest seafood resource to your capital which is missing its fishing boats is not the lobster between the continents, but the crabs north of Sydney where you stationed your war galleys after it had already been plundered by a canoe. I think something around half the seafood resources inside your borders have no fishing boats on them as of the end of episode 20.