I have two SP hubs, one of the higher end Shimano dynohubs and a couple of the low end Shimano hubs. I think the SP hubs are the best of that group. I have no experience with the SON hubs, can't comment.
Regarding wiring, the Shimano hubs are grounded to the frame, the SP hubs are not. I find it easier to wire things with a frame that is not grounded to the hub, in other words I think the SP is better in that regard.
Headlamps - there are a wide variety of headlamps at different price points and different manufacturers. i won't suggest a specific one but I will suggest you get one that has an asymmetric beam, a low and wide beam that does not waste a lot of light above the horizon. Some of the lights are like a flashlight, half the light is above the horizon and not very wide. Somewhere on Peter Whites website there are photos of some light beam patterns. Peter White also has a lot of very good information on dynohub lighting, but that is all slightly biased towards the stuff that Peter sells. You could probably learn a lot by spending some quality time on Peters website on lighting.
Taillights - for several years I stuck to battery powered taillights. I recently bought some dynohub powered taillights too, but I consider the hub powered lights as a suppliment to my battery lights, not a replacement. I often use a flashing taillight in daytime, dynohub powered taillights do not flash. Also dynohub powered taillights are wired to the headlamp, are only on if the headlamp is on. And when the headlamp is on you are not charging batteries. That is why I mainly rely on battery powered taillights.
Chargers - There are several options. I have two that are combined with headlamps, one that is charger only. More on this below.
My last several tours I almost never rode my bike in the dark, thus I am tempted to not even bring a dynohub powered headlamp on future tours, might just use a battery headlamp for the few times I might need it. The dynohub on my tours is used a lot but almost exclusively for charging devices.
Several days ago I wrote a very long post on another forum about my charger experience. I am too lazy to repeat it all here, look at this post:
Charging iPhone on the road
If you are putting this on a Lynskey Backroad, that suggests to me that you can spend a few more bucks and not mind doing so. I have a Luxos U headlamp and USB charger. Expensive, but I think it is a very good way to go. I bought my Luxos U from an internet vendor in Germany for a much lower price than they sell for in USA. The Luxos U is on my Lynskey.