The last two days my friend and I have been trying to finish off our Lilith altars to be ready for season 1 and I think everyone is doing the same. Every time I roll up to an altar at least one person but usually two or three people come charging in on their horse. It's fun to be here at the start of this game's journey and seeing everybody getting ready! I think I'm gonna try Druid when the season starts ๐ป
If you make a new character to be a part of the season, yes all side quest will be reset as you are playing a different character. Only campaign completion, alters and map explore will carry over to a new character.
Nothing happens to your current character though, nothing is deleted and nothing is reset. You can continue on that character forever, you just will not be a part of the season.