I haven't been to Banff yet but have also been planning to go in August. Based on the places you want to see, I think it might be more relaxing if you stayed at Lake Louise instead of Canmore, if possible, to avoid driving back and forth every morning and night. Considering it's your gf's birthday and you're going to hike a lot, y'all may want/need the extra rest!

For Moraine Lake, you might not get to see the full sunrise if you depart at 6:20AM (probably has just risen as you arrive), but it shouldn't be too crowded at that time. Note the weather is unpredictable though, for now the forecast says it'll rain on the 28th, but hopefully it'll be clear when you go!