I think both names are great and both work as [name_m]Adrian[/name_m] middle.
Adrian [name_m]Josef[/name_m] – With [name_m]Josef[/name_m], this combo feels like an old soul with european roots. To me, [name_m]Adrian[/name_m] is a sparkly name, it has the -ian ending that I love so much. It feels youthful but not childish. [name_m]Josef[/name_m] on the other hand, is a solemn name (imo), and I really like this spelling because the name itself has a sound that I love and [name_m]Josef[/name_m] make it looks more interesting.
Adrian [name_m]Soren[/name_m] - I like [name_m]Soren[/name_m] too, but to me this name has a dark twist, sort of “dark academy” style. It’s great, though. Maybe both name ending in -n clashes a little, but is not a dealbreaker.
Looking at your UC, I have the feeling that [name_m]Adrian[/name_m] [name_m]Josef[/name_m] fits better with your combos.
Wow, that’s hard. I love [name_m]Adrian[/name_m], [name_m]Josef[/name_m], and [name_m]Soren[/name_m]!
I think [name_m]Adrian[/name_m] [name_m]Josef[/name_m] works the best for flow because [name_m]Adrian[/name_m] and [name_m]Soren[/name_m] both end similarly.
But they both sound fine and virtually no one says our middles aloud so I’d say just pick the middle you’re more crazy about.
I think [name_m]Adrian[/name_m] [name_m]Josef[/name_m] has better flow, though I do prefer [name_m]Soren[/name_m] as a name due to negative associations attached to [name_m]Josef[/name_m].