Don't stress about it. You will be fine. Mother Nature may throw some snow your way in the higher elevations - such as in the 1st 8 miles -but several hikers are starting in Feb, so if you watch their posts, you'll have an idea of what's ahead. And, of course, up date your information for those coming behind you. I am guessing you won't need an ice ax - BUT do not go by my idea as I stay right away from any conditions that do require such gear. Maybe someone else with real experience can chime in on that. Your bag will be fine, especially since European ratings are generally more accurate that those we get for gear on this side of the pond. Maybe for those high elevation nights you'll want extra nutrition and/or another layer. Since you've thru-hiked before, you probably will be able to always sleep low. Get into Sunnyside Canyon rather than staying up on Miller, get over the Rincons in a day, and maybe at Mount Lemmon plan a nero and get yourself a place to stay. Even if you push on to Oracle Ridge, you'll be exposed for a while and just the jaunt up from Hutch's Pool through Wilderness of Rocks to Summerhaven is a pull! Should be a good water year and the desert, we're hoping, will be even more beautiful than usual. Expect the most weather as you go north of the Rim and certainly north of the Grand Canyon until the last 20ish miles or so.