Southern magnolias are usually evergreen/ fragrant 'saucer' or Magnolia grandiflora - while northern magnolias are deciduous - Magnolia spp - and not very fragrant. It's a large family (genus) of some 200+ plants, with more being hybridized each year. Whites, pinks, red, yellows, light greens and multi-colors.
There are 2 southern magnoias which are hardy up to Harrisburg: Bracken's Brown Beauty, and Jane, but they usually sustain damage in severe winters. I grew both in the fields.
If the dead hydrangea stalks break off easily at the rootball, that's fine; just so none of the root system is damaged by yanking them out. Clean cuts are always better.
If you can see enough to prune out the rest of the dead wood now, that's good. If the foliage obscures your view, and you might nip off a finger, wait until the leaves drop in the fall. Use your fingernail to scratch the bark along the stem: green underneath is good, don't cut; brown is bad, remove it down to 1".
I always cut deadwood back 1-2" at a time until I hit green, and then stop.
On vertical stems/trunks, always make the cut on a 45°, so any rainwater runs off and doesn't lay on the cut/soak into the vertical wood, and rot out the stem or trunk.
I feel like I bought an old Ferrari, fired the mechanic that that kept it running but didn’t really know how to take care of it properly, taking it to the dealership and getting price shock and then deciding to try and do it myself.
Thanks so much for your help! Every little bit helps I assure you.