as i know, not such feature, when up to 81 participants appear per page for the desktop app, you need to turn to next page to see more participants' video.

you can check this article: https://help.webex.com/en-us/article/nc7stveb/Adjust-how-many-participants-appear-in-grid-view-in-meetings,-webinars,-andevents Grid view automatically adjusts to the number of participants that attend your meeting. By inc...

no, once meeting delete, it also delete from Cisco server side so cannot retrieve it, you should schedule a new meeting if need.

you can download WebEx meeting app from Google Play store, if you cannot use Google play, you can download this add from https://www.webex.com/downloads.html you can click "Download from Android" directly and install in your Mobile