Great question, deb. You're asking them to work with multiple shoe options, but it sounds like you don't want a full length/ankle length pant. I feel like the bootie scenario is the most limiting. There seems to be much more length leeway with flats, and certainly with knee-length boots. Given that, I'd likely hem for the length you prefer for the booties. You can always tuck under a bit if you want them shorter for flats.
Looking forward to Angie's thoughts.