Also, do we then remove the resistances from all spells like Fire Shield or Immune to Burning to preserve our hard cap?
No, because I think the player SHOULD be able to push their resistances up past 100%.
Just not for all resistances, at all times.
My numbers would allow you to have well over 100% resistance for one (but only one) element, at all times.
Or you could have 65% resist to ALL elements (with weather the storm), which you could then push past 100 by spending some AP.
The problem, as I see it, is not that the player can become immune to elements. It's that it's so easy to become permanently immune to all of them.