say i have {llanowar elves} {elvish archdruid} and {heritage druid} on the battlefield. would i be able to tap for a total of 7 mana because of each creatures ability?
No, to get the mana from the Heritage the other two will have to tap. If you tap them for their mana abilities then they are already taped. Basically you can tap them for their ability or for the Heritage's ability, but not both.