Well from reading the description it appears it is. "Includes knit liner for snow use" so since it can be used for "Skiing, snowboarding, biking, skating, kayaking, BMX " it seems like it almost has to be removable.
Just from a gut instinct I would say no the boot won't fit. However, if you have really small feet maybe. But just as a tip, you can carry boots on the outside of backpacks by looping straps of the pack through the boots or using a carabiner.