Those links lead to probably some of the worst articles I've ever read. They rank right up there with the guys that were saying squats were bad for the knees. Let's look at this list, upright rows, deadlifts, presses behind the neck, good mornings. All of these are staples when breaking into O lifting, and O lifters have probably the healthiest shoulders around, along with the healthiest posterior chains around. B/hind Neck pulldowns, I won't comment, I've never done them. The whole question about the shoulders is simple, keep the shoulder girdle in balance, with move that use all range of motions. The problem is, most bodybuilders to day just go in , bench and curl, don't do much overhead work, and wonder why it is they get impingements. Work all planes of movement, equally, in pulling and pushing, and you will limit any chances that you will have rotator or impingement problems.
As to the DL and good morning, OMG, these are some of the best I know for the posterior chain, but lets look at the GM. Keep the weight as close as possible over your center of gravity, I.E. down on the lower traps, butt back, so that the bar is close to the vertical plane the knees are in, with the shins vertical. It's a matter of hip movement, with the hams kicking in at the upper insertionsBig time assistance move for us OL types. You WILL get in trouble if you just bend down in an arc with the bar way out in front. DL. well people get in trouble with this with their ego's , trying to lift more than they can by keeping the back flat. Do it right, don't go crazy, and you will be just fine.