It's a little late for many tips since you've already done it but I'll pretend you haven't. I would not over-worry about some wood chips buried in there. Yes some nitrogen is tied up but probably not enough to hurt. Be careful adding fertilizer. Members of that family are fairly delicate and can be burned by over-fertilizing with nitrogen. Not sure what you plan to use. Compost tea might work fairly well.
When Dad planted squash he would dig a hole, put in some mostly old chicken manure, and build a hill on top of that. By the time the plant sent roots down it had a good supply of nutrients. Sort of like the Indians teaching the Pilgrims to bury a fish when planting corn.
I'd have planted the herbs first and let them come up before planting the squash. Once it starts that squash is going to grow fast, it might shade the herbs out.
I've never tried to trellis butternut squash but that should work but so will you. Expect it to be a pain to keep all of it on the trellis, it can really spread out. I think you planted it pretty close together too, you may need to thin it when it starts to rum. You probably won't have enough room on that trellis to hold all of it. I tear strips out of old T-shirts to train things to a trellis. You may find you need to prune back the plant to keep it from spreading all over the vicinity. Be flexible.
If I remember right butternut squash has a solid stem so the squash vine borer is not a problem. But watch out for squash bugs. I can't remember where you are located but the bugs are a huge issue here.
it's an experiment and you have a great helper. I expect you to get a lot of nice butternut squash. And next year you will be an expert on trellising butternut squash. Good luck!