Here from our European perspective Nagios XI is the same as Nagios 4
The biggest problem in your setup is that there is no official support for livestatus under Nagios4 (with the recent versions).
Some other cores like Naemon, Icinga2 have support for livestatus in some way.
The important question for myself would be what is the goal you try to reach in your installation?
It is possible that for your problem already a solution exists with CMK as the core component.