I think your list is fantastic. I can’t comment much on the feeling of the name in [name]German[/name] or Spanish, since I speak neither, but my general comments on my feeling of these names are:
[name]Oscar[/name]: I really like this name a lot. It feels down to earth and friendly, intelligent and modern with a hint of an antique feel to it. I’m not the biggest fan of the [name]Oscar[/name] the Grouch association, but otherwise this is a great name.
[name]Leopold[/name]: [name]Leopold[/name], [name]Leonidas[/name] and [name]Lionel[/name] are my favorite lion/leo related names ([name]Lionel[/name] is my overall favorite of the bunch, followed by [name]Leonidas[/name]). And even though I like the other two better than [name]Leopold[/name], I still really like [name]Leopold[/name] a lot. It’s got a very noble feel to it, as well as the solid NN of [name]Leo[/name].
[name]Leonard[/name]: It’s okay, just not as wonderful as some of the other [name]Leo[/name] related names.
[name]Hugo[/name]: This is a name that has grown on my a lot over the past few months. I used to be quite mediocre about it, now I think it’s a wonderful name. Feels classic and modern at the same time.
[name]Tiberius[/name]: I like a lot of these ancient ‘…us’ names, but to me [name]Tiberius[/name] just sounds too ‘heavy’.
[name]Cornelius[/name]: I quite like this name, though the fact the beginning of it sounds like ‘corny’ is not something I like a lot. It’s one of those names I appreciate, but just couldn’t ever bring it around to me own list of possibilities.
[name]Benedict[/name]: Not a fan of this one. I don’t like most of the [name]Ben[/name] names (partially because of my connection to the Chinese language, where ‘ben’ means ‘stupid’), and of them this is one of my lesser favorites. ‘[name]Ben[/name], a dict’
[name]Arthur[/name]: I like it a lot. I often put it in the same mental category as [name]Oscar[/name], feels modern and antique at the same time. Solid option.
[name]Lucius[/name]: Is one of my favorite names ever. If it didn’t sound very similar to a family members name, this would be high high on my own list. Great great name.
[name]Lucio[/name]: This is solid too, though I like [name]Lucius[/name] quite a bit more.
[name]Lucas[/name]: Is also a really nice name, but [name]Lucius[/name] stands out to me as more uncommon/meaningful/interesting.
[name]Carsten[/name]: I’ve never heard this name before, but my first impression is pretty negative. It feels like a modified version of [name]Carson[/name], which I also don’t like.
[name]Titus[/name]: Again, similar to [name]Tiberius[/name], feels heavier than a lot of other old Latin names (my favorites being [name]Amias[/name] and [name]Caius[/name]). Plus the first three letters being what they are is not particularly cool for a name.
[name]Theodore[/name]: Can’t go wrong with it. It’s timeless/classic and solid.
Niklaus: Mediocre. No strong feelings either way.
Leofric: I prefer [name]Alaric[/name] and some of the other [name]Leo[/name] related names. It’s okay though.
[name]Ludovic[/name]: Not bad, but feels a bit harsh to my ear.
[name]Ulric[/name]: Again, like [name]Ulric[/name] better. It feels a bit medieval and slightly fantasy-novel-esque. It’s not terrible though.
My favorite is definitely [name]Lucius[/name], with [name]Hugo[/name] and [name]Leopold[/name] coming up next.