Gather 1000 shards per hour, possible?

[Niwashi]

If its 800+ GP, would it then be possible to use both Ward and King's Yield/Blessed Harvest on the same node?

Even if it's possible, that would be a waste of GP if you're farming shards. King's Yield/Blessed Harvest gives you one extra item for 400 GP or two extra items for 500 GP. The various Ward skills will give you eight or ten extra shards for 400 GP (two per gathering attempt * four or sometimes 5 attempts per node). If you have 800 GP, it means you get to use the Ward skill on two nodes in a row.

Those skills that up the shard rate are active skills which must be activated with GP, right?

Some are.
At Miner level 20, you get Byregot's Ward, Nald'thal's Ward, and Thalik's Ward, which increase lightning, fire, and water shards respectively at a cost of 400 GP.
At Botanist level 20, you get Nophica's Ward, Menphina's Ward, and Llymlaen's Ward, which increase earth, ice, and wind shards respectively at a cost of 400 GP.
(All six of those are cross-class skills, usable on both BTN and MIN once earned.)
At level 41, a trait makes those skills work for crystals as well as shards. Then at level 50, another trait makes them work for clusters, too.

At level 42, you also get a trait, Nymeia's Ward, that randomly boosts the yield of shards as well as any other item that doesn't have HQ versions. This effect just happens sometimes as you're gathering and doesn't require the use of any GP skills. It most often gives one extra item, but I've seen the bonus go as high as ten extra items. (This stacks with the extras received from the GP Ward skills above, so you could get 13 shards with a single swing of your axe if Nymeia gave you a +10 while you had the +2 active from the element's relevant skill.)