For the first issue, add a width of 100% to the paragraph in your Feature card, I tested on IE11 and this fixes that problem.
With IE11, you need to be explicit with a lot more of your items, whereas newer browsers will understand that the paragraph is a child and shouldn’t expand beyond that element, older browsers fail to do this, so kindly add all you text on one line.
I’ll take a look at the other issues if get chance, but try that with anything else that you have a problem with, add definitive values where they may be missing.
IE is an old browser that is not receiving any more feature enhancements. since it officially EOL. If you need support for it, then don’t user features it does not support.
+1. You’ll have more and more issues with IE11. I no longer offer support to any of my clients who may decide to use it.