I think Lin would refuse Korra's offer until she knew more about what was going on. Korra is still pretty weak and shouldn't be charging head first into things again. Lin is also sure Tenzin wouldn't approve either. After just losing his wife, he shouldn't have to see Korra in danger so soon. I think Lin would keep Korra informed if she knew Korra could listen and discuss without wanting to go out and kick down doors for answers.

Oooh, that would be interesting. I think them eventually confronting Xano and Xana would be intense.

I meant to mean that Xana would tell Asami it would help them, as well as the city's future. I think Asami would def hesitate but considering Xana seems less crazy than Xano at that point, she'd trust her. I almost feel like Xana would be developing the youthful drink on her own without Xano even knowing about it. Since if he found out, he'd of course want to turn a profit.