This is Japan you’re talking about! 70 min is fine. It’s a common connection time for Narita.

The ANA gates are in the same terminal.

From memory when I did it last July I had to take my bags to the ANA desk after I cleared customs. Just a 100 m or so after turning right in the arrival hall. They were checked through.

We had 30 min to spare. I was flying PE On the ANZ so got off the arriving plane quite quickly.