1) How many talents are supposed to be available in the box? With 4-5 players, and Soulranks increasing, there's almost not enough talents available for everyone. Are we supposed to get the background talents then, or wait for wave 2?
2) Can a hero carry more than one artefact (one equiped, and the other one(s) in their bag)? A player may only benefit from a single (equiped) artefact at any time, right?
3) What is the rank of a companion useful for? Their HP are the Soulrank of their master (hero), right?
You have enough talents for Wave 1 and the first 4 soulranks with a full party.
You can carry multiple artefacts but can only equip one.
Different companions calculate their health differently. If you are referring to the front/back side of their cards, "rank" of the companion impacts their abilities and powers.