Blending is really important for good cider. If you are going to start with apples I think you would do better with a blend of apples more like this:
50% base (red delicious, golden delicious, gala etc.)
25% tart (Jonathan, Jonagold, Pippen, Granny Smith, etc.)
20% aromatic (Gravenstein, McIntosh)
5% tannic (crab apples)
You have to grind the apples pretty thoroughly to maximize juice output. I sprinkle sulfite solution mixed with the pectic enzyme on the apple pulp as I go. The pectic enzyme helps with extraction. Then I press. If you can't find crabs you can use some grape tannin. About a teaspoon of the dried for 5 gal.
The rest of your recipe looks excellent. You are going to get a lot of sediment so letting it sit for quite a while and careful racking will be needed. Plain apple juice would get you an OG in the neighborhood of 1.055.
Glycerin isn't going to add any sweetness. You could consider wine conditioner which is invert syrup with sorbate in it. That would not work if you are going for a bottle conditioned cider. I have not been able to do a sweetened cider that is sparkling with bottle conditioning. It always ferments out dry. A bit of residual sweetness adds nice balance though, so you could consider force carbonation with wine conditioner and bottle that.
You are probably going to need 125 pounds or so of apples for five gallons of juice. Last season I ground 125 pounds of apples in a Cuisinart food processor. Tedious! See if you can get an apple grinder!
I also used a small fruit press with nylon coarse mesh bags. Also tedious, but a wine press will not work well. All in all it was worth the effort.