1. Bases will give you a „rested buff“. For workbenches/crafting tables you‘ll also need a kind of base around it. Yes there are raid events in that mobs will attack your base if you are inside.
2. It’s not infinite but very big. You csn set markers on a map to help you with orientation.
3. If you die you lose the stuff on you (including armor you wear), but you can get it back (there will be a tombstone with all that stuff where you died). You will also lose 5% of your skills.
4. The specs you mentioned should be sufficient.
5. Yes boats have storage, but not that much, also there are carts. Anyway it will be very time consuming to move an big base, better to build a new one.