Hello,
1 - Yes you can change the "root folder" for a vendor and also give him access to some "extra categories".
The Vendor root is their home ; where they can create new categories if they have the ACL
Thanks to that, you can limit the categories that the vendor can see and use for his products.
2 - The PDF plugin is not part of HikaMarket ; I can't help you with it.
But you can open a new thread in the HikaShop section of the forum.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.