I've hiked Memorial Lakes twice but never quite made it to the third lake. It is a long hike that starts out with 3 km that are pretty flat along Ribbon Creek. It's 14.8 km to the middle lake with an elevation gain of 599 Meters. It's 16 km to the third lake with an elevation gain of 759 meters.
I wouldn't have brought Baxter if I had anticipated that much snow on this September day. Poles and gloves would have been a good idea as well. Good thing he didn't mind chilling in my back pack for the 2nd half of the day.
The first waterfall is breathtaking. I'd almost argue that I would maybe even stop the hike there if you aren't up for a long day. It gets quite steep after that and I'd call it a scramble past the 2nd lake. (which is where I stopped to enjoy a book while my friends explored further to the last lake & monument).