The type coverage calculator already has an option to use the old type chart from gen 2-5. It would be nice if it could also include an option to use the Pokemon Go type chart, which differs from main series games in that immunity is replaced with "ineffectiveness" (essentially a double resistance) that stacks with other type resistances and weaknesses. For example, Swampert resists Electric, Groudon double resists Electric, and Torterra triple resists Electric instead of all 3 having the same level of resistance.
Yes, that's a very good idea! It would likely require a separate page since the Pokemon available are different/more limited.