Okay we need to properly discuss the timeline of the timeline of the Aruto vs Taro special. It literally cannot take place during Episode 29 or after.
Rampage Vulcan was adknowledged in the special. Yet in the Episode 29, Aruto is no longer president right after Rampage Vulcan's first fight. It's also difficult to smudge the special between those two scenes, since the special appears like as a normal day at the Hiden office.
Furthermore, Taro's Key is not in Aruto's possession as seen in Episode 30. You said Fuwa may have kept Taro's Key, but Taro's Key was shown to have no benefit for him. It'd be odd for him to have kept it in his possession.
Aruto would have no reason to collect Humagear data unless he know something would happen, like in the case of him being removed as CEO. How else would you explain the Zero-One Driver ending back up in the office UNLESS the special itself happened?
By the time RampageVulcan debuted, Gai had already won the competition and Aruto had handed over the company during their dinner. There would be no reason for Gai to arbitrarily wait and let Aruto continue to use the building.
Remember me? I'm Father Spice, that idiot who ruined this wiki. I'm conducting a survey on fanmade Progrise Keys. Don't worry, I'm not putting them on the wiki, FortetoBlues would kill me if I did that.
If I had my own Progrise Key, it would probably be "Scorching Dragon." Here's the transformation announcement:
Third-degree wings! Scorching Dragon! Blazing flames that will send you home in ashes.