I found it too hard to vote, balancing sounds, meanings and popularity, so here are my thoughts 
So excited to see [name]Caedmon[/name], which I love but can’t use due to past-pet-associations! They are both manly in the best way and tick the ‘unusual’ box. However, whilst [name]Caedmon[/name] makes me think ‘history’, [name]Drake[/name] makes me think ‘trendy’.
Skandar is fantastic, and I’ve not come across it before (like an abbreviated Iskandar?). But it seems much longer than [name]Drake[/name] and I might prefer fewer shared letters/sounds.
[name]Leon[/name] is the right length, with animal meaning, but softer and certainly not unusual. I think it would work.
[name]Theo[/name] is a long-time fave of mine, and I think the sound complements [name]Drake[/name] nicely. However, it is more common than his sibling’s name.
I would avoid [name]Damian[/name]/[name]Damien[/name] because of duplicating the Ds.
[name]Knox[/name] fits sound-wise, is short, punchy and trendy like [name]Drake[/name], but oh-so-Brangelina 
[name]Kieran[/name] sounds OK, but it’s much, much more popular and has far less character.
[name]Peregrine[/name] - agree with [name]Blade[/name] that it seems fussy in comparison.
[name]Rowan[/name] - agree with pp that it is very soft in comparison, and quite feminine, not very ‘[name]Drake[/name]’!