1 - On titan, the major HNM players (LS wise)
Karasu - Karasuls.com
Legacy - legacy.animeimpluse.com
Particle - particlels.com
Up and comering HNMs
HOF, Clovers, Eclipse (I don't know their LS websites)
There are a ton of Sky LSes.
Most are retired HNM people.
2 - Most good dynas / limbuses are run internally of the HNM players. There are individual groups out there. Check KI thats where Titan posts.
3 - See above for LSes. Read KI for the people.
4 - Join any LS and they'll have the list ready for you.