@kc316 Every single exercise you listed (treadmill, stationary bike, elliptical, stairs) is absolutely great for weight loss. Consistency and total duration of effort is what will matter for weight loss.
Is 60 mins on 4.5 incline going to give any sort of results?
Right now, perhaps, but this has to be continually assessed. What's your RPE after it? If it's 4-5, keep at it, and then increase intensity or duration when you have become better at it and RPE has fallen to 3.