Hi CanitoHD.
This should be fairly easy to complete. However you might want to display a message first as all web browsers need to be closed.
You can deploy a package with a message via the below command.
msg.exe /W /TIME:300 * ## FLASH PLAYER UPGRADE ## Adobe Flash Player is pending an upgrade, please close all web browsers before pressing ok to continue. Otherwise this install will force close all web browsers and start the update after 5 minutes.
After the message step you can have a taskkill command, you want to kill the processes iexplore firefox and chrome.
After that step you want to call the uninstall first.
https://helpx.adobe.com/flash-player/kb/uninstall-flash-player-windows.html#main_Download_the_Adobe_Flash_Player_uninstaller
Download the uninstallers use a condition check to uninstall the necessary versions.
Add -uninstall to the Parameters field to complete silently.
After that you could then deploy the new updated version you want, however you might need a reboot, that I am unsure of.
If you need anymore assistance, please let me know.