dk, no, you're not the only one to have noticed, for the same reasons. Once you get slammed with real poison oak, your views on it change, a lot. I have spent days in big sur laid up waiting for the swelling to go down, very nice days they turned out to be too I might note.
Poison oak is getting worse everywhere I look, it's fond of two things: co2, and sun. And heat.
So it's getting much worse, because we are creating the exact circumstances it needs to prosper, and it's prospering.
Looking at the gear list, the one item I wouldn't personally bring would be the zpacks shelter. I've spent a lot of time in Big Sur in winter, in fact, it's by far my favorite time of year there, and there's a few things, noted in this thread already, that make such a shelter not very desirable in my eyes. The main thing is that there are very few flat spots in the northern parts of Ventana wilderness, which is probably where you want to be, unless you are right on the ridges, off trail. then you can find a few, but only right in the saddles along the spurs and ridgetops.
What this translates to is that the flat spots tend to only exist in the camping spots, which are impacted, and the ground is flat. What this means is that you will get puddling during the rain under your tent's floor, which means you really want a real floor, bathtub. Now, ideally, you will be lucky, and miss heavy rains, after all, last season in CA was incredibly dry, so I'd say the odds are quite high that rains will not be really bad, but if they are, you may not be very happy in that shelter. I'd much rather be in a Tarptent with real built in rain protection, nothing against the zpacks shelters, they are beautiful creations, but just strike me as not fitting that well into really bad wet rainy weather where you can't camp on forest duff. Back when I carried heavier gear, I can remember many a rainy day in my tent marveling at how water proof the floor was, since there were pools of water under me. And no, site selection is not an option in many parts of big sur, the only flat spots you might encounter literally are the camp sites. Not everywhere, but in some areas that is the case.
The other problem is no top vents, and straight plastic mylar sheeting, aka cuben, which must be the most prone to condensation material ever devised, I can see very bad condensation in a rainy day there with that tent. Wet flat spots, by streams, non vented shelter, plus rains, ouch, that sounds like no fun at all, some guy in gear forums noted he'd had a terrible time in his zpacks shelter when he had to camp close to a lake's edge in a rainy period.
The backpack you have is good, durable and reasonably tough skinned, big sur and UL packs are a very bad match, unless you want a shredded pack, or unless you never go anywhere other than the main trailhead to sykes, actually, to Redwood up the mountain, after that, you are bushwhacking through Chaparral.
After learning the hard way that resistance to poison oak is lost, not a built in permanent thing for your body, I now take much more care about how to handle it, and read a lot from people who backpack a lot in big sur specifically on how to deal with it. UL methods don't work, so forget them: my last trip there this did work, and it was taken directly from a woman who had figured it out with her boyfriend, who was very susceptible to it.
These basic rules really help:
1. NEVER wear shorts,, period. I actually learned that several decades ago from an older guy I ran into there on a hot day, with long jeans, he noted the problem with poison oak and shorts.
2. Use camp clothes and shoes, and change into them the second you stop at camp. This really seemed to do the trick. these can be super light, but if you don't bring them, you may be sad.
3. During the day, keep your hands off the lower parts of your legs, and off your shoes. This is much harder to do than you think.
4. Tie / adjust shoelaces with gloves, ideally, thin plastic ones like you use for hair dying.
5. Bring technu extreme or something like it, and if you think you got exposed, rinse off the skin you think might have gotten exposed before you get an outbreak. Do that far from water sources, it's a very non organic substance, I think it's petroleum based, not sure. But it lifts that stuff off. There's some soaps too that I've seen recommended.
Oh, and ticks in Big Sur do carry Lyme disease, so permethrine on clothing is a pretty good idea. In winter it's easier to do the actual recommended practices, long sleeved shirts, pants stuffed into socks, or shut with elastic at their bottoms, whatever.
I disagree, with slight joke, on not camping near trails in Sykes, I find it's a great spot to camp in, that way if you had to stop at sykes on your way to somewhere good, you can be gone from it as soon as humanly possible. Last time I picked a spot that was about 20 feet or so from the Pine Ridge trail, and was able to get out of Sykes really quickly in the morning, which was great. Since everyone congregates closer to the hot springs, which are now cemented up and hardly wild at all, making, by the way, a lovely way to get everyone's poison oak oils into your skin. It's also hard to dry off in winter, by the way, which can lead to some very unpleasant results which I'll spare you the details of, particularly at night as you stay sort of damp all night.
Sykes apparently is getting even more populated on weekends, though in winter during the week it's not too bad, or at least it wasn't, but there's some weird people who hang out there, last time I actually spent some time there, I remember feeling very strange and deciding to leave before those weird feelings manifested into something not so great. I've learned to trust these feelings over the years. Once you are past Sykes, everyone you meet, basically, will be a real backpacker, of whatever strain or variant you find. Same goes if you start somewhere you have to climb a few thousand feet, that filters everyone except serious people out.
There's some loops you can do still I think but I don't know their status, I know once I just hiked down the road, or up, don't remember, towards tassajara, until I reached another trailhead, that was fine.
I never had any problems with creek crossings in winter, they get higher, but you can always get across them somehow, particularly easy if you have stream crossing shoes in winter. Cold wet damp feet all day, brrrr, no thanks re walking through stuff in socks/running shoes. Stream height will never keep you from anywhere, just means you have to slow down, take it easy, and cross it. It's fun.
Big sur in winter is really great, but the poison oak thing is for real, it's not a joke. I would love to get down there this winter but they shut down the bus service to save money, so now it's more of a challenge getting there after Labor day.
Another thing to be aware of, after you buy your map, which hopefully have gotten, is that many camp sites are really only big enough for a tent, or two. A topo map will show you spots where you can camp offtrail, it's easy to see, since big sur is incredibly steep, their contours are 200 feet, not the normal 80 feet or so, so anywhere you find space between the lines it's quite likely you will find a flat spot if you look around.
You have a good headlamp, I got my zebralight for big sur specifically, the trails are very dangerous and one slip at night can lead to death, or serious injury, so you don't want to go with any UL type gram saving headlight, you want to be able to actually see the trail, the zebralight works very well, I used it last winter on day/night hikes here in the coast range mountains, and it was great, no problem seeing steep rocky trails at all.
When I went there a lot in winter, I got a synthetic 20 degree bag, it's cold and somewhat humid, but I think I'll chance it with down until I have a bad experience, 20 degrees is fine. I'd bring a synthetic puffy though, not down, that way you have at least one thing that will keep you warm if it's damp in the air.
But don't fret, I used to watch the weather reports and head out when the rains hit, which is a balance, because from the North, carmel river bridge tends to flood out in heavy storms, so you have to watch that, and from the South, highway one is in permanent repair mode from landslides, so make sure to check both, there's no alternate routes on that stretch, at least none I'm aware of. The better your rain gear and tent, the happier you will be, but it's quite likely you'll hit just a week of cold weather with few rains now, things are changing.