Is World XI team a full member of ICC like Australia, South Africa? Is its match considered international or domestic? Would the wickets,catches,runs etc scored by a player in World XI team be included in its international career or not?
ICC members are made up of governing bodies, not teams. Therefore the World XI, which was a team directly organised by the ICC, is not an ICC member itself.
However, the matches were given ODI and Test status. They therefore do count towards official international records, and individual player statistics.