Pulling a few pieces back and carefully inspect the roof deck for signs of moisture discoloration/ damage where it had been covered. If there's none or it's minor you've kinda dodged a bullet.
Putting in a chute will prevent damage to the roof deck, but it would create a heat leak there, aggravating ice damming issues (which are also a PITA).
Ripping down a bunch of reclaimed roofing iso at roughly the right widths & lenghts to stack up on top of the studwall plate with a loose fit, loos enough to sealing in place with a FrothPak or TigerFoam kit would raise the R-value at this critical point cutting the ice-dam potential. Leave at a 1/2"-1" breather space between the roof deck an foam to above the fiber layer wouldn't be quite code (IIRC code requires 1.5") If the brick veneer is vented to the attic with a ~1" gap, preserve that gap width at the roof deck with 1" foam board, and cut'n'cobble between that and the top plate.
If you're putting unfaced R30s over the ~R19ish batts there's no reason to remove the facers. They may in fact have mold growing on the fiber-side of the facer that's best left in place, but once you have R30 above them they will stay warmer, above the dew point of the conditioned space air, and would no longer collect seasonal moisture to support further mold growth.
To get the performance out of the R-30s they have to be very snugged up to one another with no perceptible gaps or compressions, and a layer of vapor-permeable housewrap over the top as an air-barrier also improves performance (unless they're the high-density "cathedral ceiling" type.) Even without the air barrier you'll be cutting the average heat loss out the attic in half, but at the temperature extremes the R30s will be underperforming their ratings by quite a bit. (But even if they're only getting ~R25ish performance in a 10F attic that's still pretty good compared to what you have!)
Just for yuks, what's the wall stackup? If its brick/1" cavity/15# felt/ply or plank sheathing/2x4 stud-bay/lath/plaster it's possible to safely insulate the studbays, and that would cut fuel use by a significant double-digit fraction. Brick veneer over an uninsulated studwall adds up to less than R3, but with a cellulose or blown-fiberglass fill you'd be at about R10 with thermal bridging factored in, cutting the conducted wall losses by 2/3. It may be possible to insulate most of it from the attic blowing into 1" holes drilled in the top-plates, which would at least stop leaks from from the conditioned space into the walls from convecting/infiltrating to the top to deposit moisture and add to ice damming aggravation. You want to preserve the air gap between sheathing & brick, but fill the stud bays with fiber at a sufficient density to substantially block infiltration. Even low density cellulose would do that, with new-school fiberglass it takes ~1.8lbs density, which may be hard to do if installing that way, but even if it's only that density in the top 2 feet of the cavity that's HUGE from a convection loss and moisture transfer point of view.