In the trailer of pics for Upcoming ZI-O Episode, we only saw Takumi & Masato in their human form but it seems that they will also transform into Faiz & Kaixa respectively & fight.
Geiz is going to wear in the Armor of our God Kuroto Dan. Kamen Rider Geiz Genm Armor. He is going to use Zikanzax in this form.
Kamen Rider ZI-O will use OOO Ride Watch to transform into Kamen Rider ZI-O OOO Armor. This form resembles Super Tatoba Combo and has "Taka", "Tora" & "Batta" written on the chest in Katakana. If Geiz transforms into OOO Armor then his chest might be written in Hiragana. He uses Tora Claw as the weapon & his thigh parts seems to have something.
Tasuku Nagase will reprise as Kousuke Nito / Kamen Rider Beast in Kamen Rider ZI-O. He will be the one who will be holding the Ride Watch this time. May be this is Wizard Ride Watch. None of the scans show him transformed but in one of the scan you can see him wearing the Beast Ring. He still loves Mayo!!
During the fight, he will become good friends with Geiz.
Kamen Rider ZI-O Gaim Armor is going to appear in Kamen Rider Heisei Generations FOREVER. Recently Gaku Sano had posted some pics on his social media which was believed to be related to filming of Kamen Rider ZI-O. But there were some offs so it was difficult to be believed. But now when you think about the timing of Filming of FOREVER & this post, then I think that was related to his reprising.