sam2: 1.The Rambam defines an eved canani as one who has left the status of being a goy but has not yet reached the status of kdushas yisroal.Accordingly,any discussion of tevi is not on point.
2.With respect to the Lubavich minhag not to sleep in the succah their reasoning is a bit different(and perhaps even more krum) than simply “it is to holy to sleep in”. The argument,as I undertand it, is that since we can not percieve the Shichina when sleeping in the succah, as the Mittlle Rebbe apparently did, we are all mitzta’ar from the recognition of our lowly level which in turn patters us from sleeping in the succah.