Thanks for you inquiry
- I need to disable add product functionality on seller interface or limit it only to product description and images, we don't want seller to set price and other attributes. Can i edit module file to achieve such functionality (at least one)
Yes. Most cases you can modify theme file to archive that.
In case you need modify related PHP code, we will provide your with open code file for your customization purpose.
- I need to assign sellers to products that i create but this functionality is not working on demo site
It should be working fine, tell me which demo site and I can have a look at it.
You must choose sellers from the drop down list and then use check box to select products, and then choose "Assign To Seller" from the bulk action buttons at left bottom corner of product list page at back office Catalogue.
- i will have multiple stores (3) with same sellers what else should I purchase to make the whole system working?
I am sorry , i am not quite sure what is your this questions.
Please note, we are not using PrestaShop original multistore feature, we use our virtual shop concept to allow each seller has a virtual.
If I understand correctly, you will need register 3 seller account.