I am no expert but I have read that pine needles are alkaline on the PH scale. Hydrangeas love Acid. That could be one thing. I would move them to a place that gets morning sun, afternoon shade. I have one that gets morning shade afternoon sun and it does fine.
When you plant it put either some instant PLAIN (no lemon or sugar or sweetener)tea granules or plain tea bags on top near the roots (this is acid) and water lots of water. Hydra=water these plants need tons of water. I water mine some times 2 times a day in the hot weather. Like I said I am no expert but I have had one for 4 years now with no problems. I helped my neighbor get hers blooming again. Let me know if this works/helps.

What it says above. Wilting=need for water. Probably just that coupled with transplant shock.
P.S. let us know how your Glowing Embers does over the long haul. I have a few and I'm not impressed.

Pine needles are not alkaline and have no long term effect on soil pH. The wilting is the result of too much sun - bigleaf hydrangeas need shade from the hottest part of the day, so a morning sun, afternoon shade location is preferred. And anything recently planted, specially at this time of year, will need frequent watering just to get established, let alone a shade preferring plant in too much sun.

ES should be fully hardy for you, but Glowing Embers will need winter protection.

My hydrangeas are in full sun and they love it, but it does require attention to their watering needs. I think it's true in warmer zones that they can only deal with morning sun. Not necessarily true in Zone 5 IMHO.
I have Annabelle, Limelight, Nikkos, All Summer Beauty, Endless Summer, and a florist lacecap that winters over just fine. They all have enormous blooms right now on healthy, full bushes.