All of the WInter City elves are Boreal or Pale elves: resistant to cold, tall and muscular. The schism between the old believers and the new Lumian faith was entirely religious, so both sides of it still are - and consider each other to be - boer'alvar.
Wyld Elves are an entirely separate subtype of elves that are native to the temperate woods of Old Belhar and its surroundings. A mix of High and Forest elves if you want to like them to elves in other settings, with some fey-like traits thrown in. Their Codex entry doesn't talk about the religious practices they had before adopting the Seven, but given that they have a strong connection to the forest and the spirits, it's quite possible that they worshipped one or several entities that are similar to the Old Wyld - if not the Old Wylds itself.