This is interesting. Unless I missed something from the books (or am just misremembering), all sirens shown so far have pale skin - but since the only "requisite" for being a siren is being a woman, non-pale skin could be a thing.
I don't think this is the case thinking about it. Commandant steeple certainly does but outside of that you can only reasonably make a case for Angel having pale skin and that could and very likely is down to her being held captive
Adding some new Info to the OP
New Element - Nuclear
Used to combat "Bio Armor" apes on Eden-6
Looks like all prior elements will return