That stuff is all nice, but as you yourself noticed that stuff is not the actual Drikung Kagyu stuff. He's very open about a lot, but not the Chakrasamvara tantra, five-fold path Mahamudra, Six Yogas of Naropa, Etc.
He did not study six yogas in depth, his words not mine. This is why he does not teach it. During a teaching on tsa,lung,tigle, Gar Rinpoche said that if you want to learn these things in the context of the six yogas then go to Traga Rinpoche since he studied and mastered them. As well, Gar Rinpoche did not establish the Demchok retreat in Arizona. Drupon Rinchen Dorje was instrumental in that, as he is the Drupon there and wanted to begin that.
When he does give a Demchok empowerment, the commentary I have heard on audio, and the transcript I have read are full of detail that I wish I would have received during retreat.
As well, the Yamantaka Terma that Nub Sangye Yeshe hid and was later revealed is Given all over the world by Garchen. That is considered an extremely precious lineage that Drikung holds and Gar Rinpoche was criticized by some for letting lay sangha participate.
If his main practices were demchok, six yogas, five fold path etc. he would not keep them under lock and key.
He gives the Ganges Mahamudra often which is the heart of Drikung when it comes to Mahamudra practice instructions.
But, yes it is still conservative in drikung, as it is in many lineages.