Forum permissions, BBCode, Country field in order

Hello,

I have a 3 question:
Is it possible restrict permission for create any post, forum etc - for all user except of admin, or other role group?

Second question is about BBCode - I would like create forum post with url in Iframe.
I do not know how...is there any way?
for example Add user defined code to bbCode editor  (where/how),.... ?

thirth question is about Order....
Adress data for invoice required Country field. In configuration - settings - Customer settings-> 3. tab (adress setings) it means for order..there is a checkbox the State is enabled....
In the order form the field is mandatory, but I  would like to have the field as unreqiured  - the customer does not must fill this field as a company name. Unfortunetaly there is any checkbox for State is required....is there any way?

Thank you
David
version nopCommerce 3.9

1. This feature is not available out of the box and will require some customization. original link
https://www.nopcommerce.com/en/boards/topic/91898/user-permission-in-forum
2. --
3. You need to modify State validation logic of AddressValidator