[Mick]

I thought the Giants won the tiebreaker due to the H2H record?

I think the better H2H record only gives them the right to host the if-needed play-off game 163.

Does that mean that the Giants and Dodgers would essentially be playing game 163 where the loser has to play game 164 against the Cardinals and the winner gets home field that NLDS which (given their records) would itself also be Giants and Dodgers?

Yup.

[Mick]

I thought the Giants won the tiebreaker due to the H2H record?

I think the better H2H record only gives them the right to host the if-needed play-off game 163.

Does that mean that the Giants and Dodgers would essentially be playing game 163 where the loser has to play game 164 against the Cardinals and the winner gets home field that NLDS which (given their records) would itself also be Giants and Dodgers?

Yup.