People on reddit, any type of forum for this game would definitely find these exotics. Spindle and Sleeper were all found and gotten, after a hour or less of searching in missions. (when they were released spindle and sleeper missions were different days). I don't think after 8 months there would still be hidden exotics. And just so we are clear here, we are also missing Fire thunderlord and i think Void thunderlord (not to sure about this one). And in Y1 launch of destiny obsidian mind was shown in a trailer and was hidden behind TDB. You can guess the exotics listed above are in the same boat as obsidian mind...