Naruto has boundless curiosity- so when he spots a seal he recognizes from the Scroll of Sealing he activates it. He wasn't expecting a genin team from the Founders' era appearing and demanding to be taken to the Hokage! Naruto has no idea who he's summoned. Team Toka is here to stay- and throw a bunch of plans off-kilter too.
Even after Tobirama-sensei's death, Koharu still trained with Touka.
(Mito and Touka, surviving as the last of the founders left, drinking tea and talking.)
The alliance between their clans was still shaky. But they were not. They strived to gain acceptance from those they loved.
Sometimes caring for your family is getting your caffeine-addicted cousin out of his office to go bowling with the rest of your family, as Touka knows very well.