@0bacon
Hello!
AirVPN Suite 2.1.0 Release Candidate 1 is available. It addresses some problems related to your case and features a stricter check to avoid entering entire subnets for the namespace. A single address is required (in your case, anyway, you can also rely on automatic choice, since you're behind a NAT). Feel free to test the new Suite version and check whether the problems are resolved.
Bluetit is linked statically against libxml2 so the problem is Cuckoo-only in the 2.0.0 Suite. On Suite 2.1.0 version, Cuckoo is no more linked (dynamically) against libxml2 because it does not need it anymore and the problem gets solved for Cuckoo too.
Kind regards