One thing I missed in criteria in the OP (it might have been said already, didn't have the time yet to read the rest) is plausiblity check on the promised (and delivered) returns. I've done some cloudmining (product) reviews in which I mainly focus on the returns, and based on that I dare to draw even stronger conclusions than the OP did (for two companies).

CoIntellect and ltcgear are both listed as "(very) suspicious". For these two, their product offers are truly absurd.

For LTCGear (full review) I determined that they offer the equivalent of at least 30% ROI per month (take a moment to consider how fast you'll be a millionaire if that holds), and for Cointellect (full review) I even found that they promise (and deliver) more mining income than mathematically possible.

And of course this makes sense for a Ponzi scheme. After all, it is required to attract not only new users, but also keep drop-off rates low and reinvestment rates high. In order to achieve that, the outlook needs to be better than anything else. Hence excessive returns should be one of the criteria. Certainly not the only one by the way, I limit myself to this because I'm reviewing products - not exposing scams (well I end up doing that for some, but that's not the goal).