Yes, it is possible. You have to select the “Product” options type and populate each option with one of the existing products in your shop. For more details, please, refer to this page.
Yes, it is possible. You can find the “max” field available in each options set.
No, it is possible to copy the configuration to a different site. Yet, you can do it manually by copying the following tables from the database:
“yith_wapo_groups” and “yith_wapo_types” (for version 1.x)
“yith_wapo_blocks” and “yith_wapo_addons” (for version 2.x).
No, our Product Add-Ons plugin does not work with REST API.
You can do that from the price settings in the options Populate tab. Please, refer to this page for more details.