minimum requirement

Hi Community, I'm interested in buying a license for XenForo. When I checked the requirement script on PlanetHoster - World Platform, I got these warning. Your server has disabled a core PHP function proc_open via the disable_functions directive in php.ini. This may cause unexpected problems...

The add-on adds two new usergroup permission: Create Conversation: Min Post Count Reply to Conversation: Min Post Count If a user does not have enough posts to start a conversation, they see the "no permission" error when they try to start a conversation. If a user does not have enough posts...

As above, I'm speaking of storage space, bandwidth, number of MySQL connections - not software requirements. These are usually specified by hosting companies on their packages. Unlimited options are tempting but based from my research, its seems these are not really true. The reason I'm asking...