The number of fingers doesn't matter as long as is capable of detecting at least two. "Comprising" is non-limiting, so if it detects three or five fingers it might still infringe.
As for minima/maxima, you have to look at the rest of the patent to figure out what that would mean to a person having ordinary skill in the art. It seems to refer to a signal that varies from 0 (no touch) to some large value (solid touch), with a minima being a small value and a maxima being a large value.
But that's just it - that description implies they are detecting differences between the fingers, a primary, and a secondary of a different qualitative nature. Even with the 3rd party apps that unlock the various Apple multitouch properties all the fingers are the same - one might be doing something different than the other(s) but there is no 'maxima' fingers as opposed to 'minima' ones, just presses which are in themselves all equal - only what action they may be taken is different.
If that is the crux of their patent I would say that apple is not currently infringing on it - a press is just a press on all the apple products I have.