This is WAAAAAAAAAAAAAAAY too early and even if you want to place your bet on WD, it would be completely premature to now attempt to call out every detail of what you asked for.
As I mentioned in the other thread, the meta is still very much influenced by the 2.4.1 meta because 99% of the people playing PTR are non-competitive players who copy builds rather than theorycraft their own. Most knowledgeable players are too busy farming/pushing on live. Also, the one thing we can tell from PTR is that DH is in no way out, it might actually be the second best support class (after WD) next season. No, no one can tell you what gem/gear will be used on the DH as it's not thoroughly tested it, it would just be guessing and completely bogus.
As for the WD, the WDs on PTR are running almost exactly the same stuff as on live, so just look at current live leaderboards and check out popular WD support builds. If you honestly want some premature answers to your question check out the support builds in our build section.
Yeah, like that. I personally think you'll likely ditch Thing of the Deep (there will be no health globe spam anymore) and take up Wormwood (which is what many WDs are already doing on live). Most of them use Cloud of Insects (though I don't know why, I think I'd prefer Pestilence for even more spread). Hex might go back to Jinx (depends on how crucial pulling is), and of course many WDs might actually prefer Spirit Walk in their build as it becomes pretty much of a gamble otherwise. And Toxin gem might see a comeback if (big if) the lag is fixed.
But all that is so much guessing. There's also still this 1% hope (or even less, to be honest) that they finally make the WD's damage competitive enough to be part in the group's meta, so you could run a hybrid of some sort.