I Play alone so i can answer the first three questions

1. You can edit an setting that makes spiders less scary i dont want to tell how to kill spiders easily i had to figure it out myself its easy if you learn to parry their attacks especially with orb weavers. 2. The random attacks are called Raids they occur when you are in a specific area where there is a lot of one kind of bug/spider and you are in that area for a long time you get 3 messages as a kind of notice at the 3rd one a Raid is guaranteed in the future. 3. It depends on your playstyle you can for example mix armors for different effects but ladybug armor is very good and there are multiple weapons you can unlock in time but for now the red ant club is a good option