Q1) does this extension support multi-language store? ?
Yes, it supports multi-language site.
Q2) is this extension support multistore? ?
Yes, it supports multistore. If you add an offer on products. The offer would apply to all stores where the product exist.
Q3) does it use vqmod or ocmod ?
We follow opencart standard which is ocmod. So this is ocmod.
Q4) Will the offered product added automatically to cart ?
We have Add bundle feature button present on the product page. When this is clicked all products are added automatically.
Q5) will the offers apply to all stores or the default store or to a select store or to all user groups or to the default user group or a select user group? ?
It would apply to all stores. You have the option to select customer group. If none is selected it applies to all users by default.
Q6) does this support custom theme ?
Yes, it does support the custom theme. Sometimes no configuration is needed and sometimes minor configuration is needed. We offer configuration option with the theme if it does not work.
You can create a support ticket on our website
Q7) Can we create all kinds of offers using this extension ?
You can create the offers from the techniques mentioned on the extension description page. Outside of that, the module is not responsible. As it is beyond module's feature list.
We can offer customization if we think it is possible. It is subject to your need.