Hello Nisol,
I hope you're doing good. As for the options, you wrote yes, they are available in sellacious.
1. Sellacious is multivendor, so multiple sellers can sell the same product for different price and stock.
2. Each seller can set the item condition of the product. In sellacious, there are three types of condition: New, Used and Refurbished. For used and refurbished there are 4 types of condition: Like New, Average, Good, Poor.
3. You can select the option "Shipped by the Concerned seller" from global configuration. That way sellers can set flat shipment cost or rules for their products individually.
4. If an order contains 2 products of 2 different sellers, both sellers will have the amount based on their product.