You could wait till you draw Kage, they both have good ninjas in there, probably the 2 mains that benefit most from that treasure.

water main, gnw tenten, ao, and iruka for good shields and 2 interrupts
plus gnw tenten adn water mains power gets boosted really nicely

Sure, although it'll take me some time to save up those scrolls :P

I have gnw tenten and ao, but not iruka. Are there other good ninjas that can replace him? Maybe mabui or chojuro for their passive once I get them?

Lightning main grants you the tenten nuke right out of the box with bloodthirsty and his 4th standard. The problem with that is his other uses are limited, and taking bloodthirsty means you cannot take root of the warrior - which is a huge trade off. However you will have quite a bit of freedom in your other two choices of ninjas, and there are many solid f2p lightning characters you could add to the team. Even not using tenten; ninjas like Danzo, Darui, Mifune, or even Chojuro are a huge force amplifier to a Lightning team.

Azure fang grants more natural synergy with tenten, although if you want to do the first turn 1010 nuke, you would need some consistent chakra acceleration (such as mabui). This does open the door to a pretty hot team right now (Azure, mei, mabui, GNW tenten) but even if you don't have those ninjas AF works well with others - sailor sakura for instance is a nightmare when paired with an azure fang.