Turn off screen tap sounds:
tap Windows button, tap SEttings, tap Sounds & Notifications, clear tickbox for screen taps, etc. (Events for the menu sounds).
Also, for 1. and 2. you could use TCPMP (at
www.corecodec.org) for playing both audio and video files. It has the supports the most formats.
And there
are some good free software round-ups on Aximsite.
(X)