Hello there house mom
Welcome to your trial on Atys.
Allow me to try and answer some for you.
1) Yes, there is mounts and pack animals
2) Players can buy a homin apartment, guilds can buy a guild apartment.
3) End game depends on your personal preferences really i suppose; there is named and boss mobs that drop rare quartered materials that are highly priced by crafters; there' s supreme kitin larva to be dug, which is the most priced harvestable raw material; there' s Outposts on the horizon which will boost the GvG/PvP in the game; there' s events on a regular basis: both player and official, there' s encyclopedic rite missions that let you gather long lost lore of our ancestors, ..... Point is there' s actually tons to do that even I haven' t done after 8 months of play; but again, it all depends on your preferences and drive to get there I guess.
It should be fairly easy to get into the story arc' s; there' s a nice lore section on the official forum; I suggest that would be a good place to start to get a general idea.
Grouping is fairly necessary at some point as Atys is a dangerous place to live and unless you have major sneaking skills or a major constitution, you won' t have seen all of this wonderfull yet deadly living ecosystem. Solo-play is viable up to some point; after that it becomes a lot harder, unless again, you have loads of time and won' t worry about that.
I hope these aid you a bit.