Dji has a wifi base especially for the Pocket so that you can connect it with your phone. (it has nothing to do with your building wifi) Use the original OP holder to put it on a selfiestick ( with that holder you can leve the base on the pocket). Smartphone holder underneath the selfie stick and you can play as you want with your gimbal, no problem at all.
Amazon.com : Selfie Stick,MOCREO Selfie Stick Gimbal Stabilize with LED Light Smooth Video Record Extendable Anti Shake Selfie-Stick-Remote-Control-Tripod for Live Broadcast Compatible with iPhone&Andriod : Electronics
How can I mount the Gimbal? I meant to remote control OSMO Mobile 3 Gimbal as indicated on following video;
Zhiyun SmoothQ App - Getting the Most Out Of Your Gimbal (includin to remote control Gimbal)
For remote controlling the mobile phone via another mobile phone there are many solution on Internet.