Helping with understanding classes & servers

Looking to get into BDO and i've got a couple questions. I'm living in SEA region and was wondering if the state of pvp is relatively active? Was also wondering if playing in NA is viable (from Malaysia) as i see a lot more active NA streamers and community on twitch ( unsure if that's just a NA thing).

Secondly, i wanted to ask about class differences. could ya'll help me differentiate Succession Ninja & Succession Kunoichi from what's available in their kit, playstyle, which relies more on stealth, movement, which is more largescale and which is more small scale. A breakdown of the differences would be much much much appreciated <3. I'm trying to see if BDO is the game for me and i'm just a little confused about both these classes cause they look pretty much the same and i'm not too fussed about which one is better over the other.