Brother is [name_m]Leopold[/name_m] (nn [name_m]Leo[/name_m].) Only name we both like is [name_u]August[/name_u]/[name_m]Augusten[/name_m] and I’d like at least two top names to choose from.
[name_m]Lachlan[/name_m]
[name_m]Roman[/name_m]
Are they too top 100 or two L’s too much?
Personally I think [name_u]August[/name_u]/[name_m]Augusten[/name_m] is perfect with [name_m]Leopold[/name_m]! If you want a second name I’d go with [name_m]Roman[/name_m]. [name_m]Lachlan[/name_m] just feels so stylistically different from [name_m]Leopold[/name_m]. I don’t care for them together. [name_m]Leopold[/name_m] and [name_m]Roman[/name_m] work, but I still prefer [name_m]Leopold[/name_m] and [name_u]August[/name_u]/[name_m]Augusten[/name_m].
Another vote for [name_u]August[/name_u]/[name_m]Augusten[/name_m]. I love [name_m]Lachlan[/name_m]/[name_m]Lochlan[/name_m] too and if the diferent styles don’t bother you then I would keep it as a contender as well.
Is [name_m]Lachlan[/name_m] stylistically different because it’s a Scottish name and [name_m]Leopold[/name_m] German- or? I get that they sound very different, just wondering if it matters in the long run.
Thank you for the feedback so far!
I wouldn’t worry about them being stylicistaclly different. As my mom told me… ‘They are indiviual people, why do their names need to go together?’ 
My kids names don’t really ‘go’ together but I love them all and they each have a name that suits them. If you like [name_m]Lachlan[/name_m] leave it in the running!
I agree with @bluecurry. Each child is an individual and you should go with the name that you love the most. Yes, by stylistically different I think they feel like they originated in [name_f]Scotland[/name_f] and Germany (although that is fine).
[name_u]August[/name_u] is the best. I don’t really care for either alternative, but if I had to choose I’d say [name_m]Roman[/name_m]
I think [name_m]Roman[/name_m] and [name_m]Leopold[/name_m] are perfect together. They have the same feel, stylish and a bit vintage. I prefer [name_m]Roman[/name_m] to [name_u]August[/name_u], but it also works.
[name_u]August[/name_u] or [name_m]Augusten[/name_m] is your winner [name_f]IMO[/name_f]. The other two feel overshadowed by [name_m]Leopold[/name_m].