I know the styles of these names is all over the board. Please comment on each as a brother for [name_f]Thalia[/name_f]. (Not expecting, but trying). Middle name will be a Chinese name given by the grandparents.
[name_m]Amias[/name_m]
[name_u]Alden[/name_u]
[name_m]Acacius[/name_m]
[name_m]Simeon[/name_m]
[name_m]Simon[/name_m]
[name_m]Cyril[/name_m]
I love [name_m]Amias[/name_m] and [name_u]Alden[/name_u] best. [name_m]Simeon[/name_m] or [name_m]Simon[/name_m] is also handsome. I prefer [name_m]Cyrus[/name_m] to [name_m]Cyril[/name_m]. [name_m]Acacius[/name_m] is not my style.
My favorites of your choices are [name_m]Simon[/name_m] and [name_m]Cyril[/name_m], with the runnerup being [name_u]Alden[/name_u]. They all fit well with [name_f]Thalia[/name_f] and have plenty of potential nicknames.
Another vote for [name_m]Amias[/name_m] with [name_f]Thalia[/name_f]! Perfection!
Yay! [name_m]Amias[/name_m] is my favorite right now too 
My previous faves were [name_m]Jonas[/name_m] or [name_m]Silas[/name_m].
[name_m]Amias[/name_m] - not sure.
[name_u]Alden[/name_u] - cute. Maybe too bland with [name_f]Thalia[/name_f].
[name_m]Acacius[/name_m] - not my style at all.
[name_m]Simeon[/name_m] - My sister had a close friend named [name_m]Simeon[/name_m] growing up, and I called him [name_f]Cinnamon[/name_f] ALL the time. They’re 11 years older than me and I couldn’t say his name at all. It always came out [name_f]Cinnamon[/name_f].
[name_m]Simon[/name_m] - I love [name_m]Simon[/name_m]. I think it’s my favorite of your choices with [name_f]Thalia[/name_f]. Another option would be [name_m]Sebastian[/name_m].
[name_m]Cyril[/name_m] - All I can think of is [name_m]Cyril[/name_m] Figgis from [name_m]Archer[/name_m], which counts it out for me. But I don’t think many other people would think of that character.
My vote goes to [name_m]Amias[/name_m] with [name_f]Thalia[/name_f]. Another name that came to mind that is nice with [name_f]Thalia[/name_f] is [name_m]Elio[/name_m] as both have a Greek background.