Assuming your primary delivery is 1080i59.94, and your system can handle it, you might edit at 1080p59.94 and then output at 1080i at 60 and 50. I’m not entirely sure the end result will be better than editing at 1080i (your best alternative) but I suspect it will. This is the “biggest container” principle. 1080p60 is “bigger” than any of your source formats so no data loss on the way in, minimizing loss in the process and on the way out. Plus, Premiere does not handle frame rate conversions optimally in the timeline, so “uprezzing” to 60 and then converting to the target framerate using encoder tends to work better.
Only peripherally related, I’ve used 60p mastering as a method for “deinterlacing” 1080i, though you have to actually deliver at 60p for this to work properly, which is still not routinely possible.
Also you’ll need a system capable of managing a 60p timeline.