Ilyzaelle is a good choice. And yes, it's extremely active. Here's also an active Discord group full of players from Echo that went on there: https://discord.gg/XQXsvTS
On your question if 200mk is enough for a PvP set it's all based on character you're playing and how many sets do you wanna have.
And Retro is/has falling/fell apart due to recent rollback because of one more duplication exploit. So I don't recommend you playing on Retro, unless you wanna quit very quickly fully disappointed you ever started it at 1st place.