Re. SON delux versus (new style) SON 28:
If you are convinced that you are *only ever* going to use the output from this hub dynamo to power LED bike lights,
then I think that *either* SON hub dynamo is equally adequate and the delux is very slightly lower rolling resistance.
But if you ever want to use the output for anything else, then I'd definitely recommend the "28".
Also, if you *ever* want to consider switching to disk brakes,
then it might be worth ordering a disk-compatible version of the hub, even if you use currently plan to use rim brakes
because it is an expensive proposition to buy another SON hub simply to convert to disk brakes.
Re. "Edelux 2" or "Luxos U"
My bike has "SONdelux" + "Edelux (1)" both in red. My spouse's bike has new-style "SON 28" (silver) and a Philips Saferide 60 (black).
Out of these two, whilst I like the aesthetics of the red SON hub matching the red Edelux
and I personally prefer the light-sensor-control of the Edelux over the simple on-off switch on the Saferide
and the OEM mounting bracket on the Saferide is a bit feeble and needs swapping out for an Edelux bracket,
I still think that the Saferide is the better light.
The Saferide has, in my opinion, a better beam pattern (than the Edelux (1))
It is just about as well engineered (modulo the mounting bracket enhancement)
It is considerably cheaper than the Edelux
But if you have the requisite funds and the colour scheme aesthetic appeals, then I am sure that the (blue) Edelux would be an excellent choice.
As I have no experience of the Luxos U I cannot make any valid comparison / comment
and this light gives you a number of other features.
If USB charging is definitely of interest then you might also want to consider the "Axa Luxx 70 Plus"
http://www.axa-stenman.com/en/bicycle-components/lighting/dynamo-head-lights/luxx70-plus/Re. mudguard-mounted rear light and cable routing:
In my experience lights mounted on the lowest end of the rear mudguard are a bit vulnerable to getting bashed / knocked
and in the end fatiguing the mudguard with the extra weight.
(I am even considering removing the tiny reflector and replacing it with high-grade retroreflective tape as it too catches on things)
So If the mudguard is indeed the only mounting point available I would suggest mounting the light further up the mudguard which puts the rear light at a better height too.
Maybe, with a bit of ingenuity you can work out how to mount the rear light at the mudguard stay attachment point.
If you are going to route cable *inside* the mudguard then it probably needs *gluing* in place
as any "hanging" bit of wire will eventually get destroyed either by coming into contact with the tyre, or just general abrasion from road debris.