Ref[1]: Of the few studies identified for each outcome, most had few participants, were of short duration, and their methodological and reporting quality was limited; therefore, confidence in the reported results is limited.
Ref[2] only states NSS should not be used in weight control due to a lack of long term evidence (I.e. if trying to achieve weight control there are better strategies, not necessarily a condemnation) as well as: Because the link observed in the evidence between NSS and disease outcomes might be confounded by baseline characteristics of study participants and complicated patterns of NSS use, the recommendation has been assessed as conditional, following WHO processes for developing guidelines. This signals that policy decisions based on this recommendation may require substantive discussion in specific country contexts, linked for example to the extent of consumption in different age groups.
Ref[2]’s full WHO review article[5] is even more damning on the methodology. Pertinent to your arguments: The results suggest that, in the short term, NSS use may lead to small reductions in adiposity without any significant impact on cardiometabolic risk. There is suggestion of negative health effects with long-term use, but the evidence is ultimately inconclusive.
Ref[3] is obviated by ref[2] and meaningless in isolation, reasons described in the 200 page WHO report.
Ref[4] is theoretical about mechanisms and provides no empiric evidence of anything. Contrary to this hypothesis the WHO study elaborates on why the long-term observational studies are discordant with short-term RCTs and the gist is bias.
[5] https://apps.who.int/iris/rest/bitstreams/1417548/retrieve