For issues 1 and 2, maybe you use an ad-blocker or script-blocker that's causing issues?
Click the Menu icon (three lines) then Extensions and Themes, and see what you have. You can try disabling one, closing Firefox fully, wait about a minute, then re-load Firefox and see if you can identify one that's causing the issue.
By-default, extensions also don't work inside "Private" windows, so try going to the Menu then "New Private Window" and see if sites work in there with no issues. If they do, it'll definitely be an extension.
As for the mouse-scrolling issue: sounds-like a setting has changed. You can get to the hidden settings for Firefox by typing about:config into the website-address bar, then press ENTER. I'd suggest searching for mouse , scroll or wheel and tick the "Show only modified preferences" box and it'll only show results where a setting is not the default. Otherwise, maybe you have some sort of screen-recording, cursor-control or eye-tracking software on your PC or laptop that is interfering with the mouse in Firefox?
If you really find you can't resolve the issues, then:
Use Menu > Settings > Sync > "Turn on backup" to backup your bookmarks, history and passwords
Then Menu > General > Settings (under "Profiles") > Manage profiles > then tap "Create a profile"
Then in the new profile, Menu > Settings > Sync > Restore your data to get your data back
Note: you'll only find this backup option under "Sync" if you're using the latest version of Firefox; if you're on the ESR version, it probably won't be there, as that is currently around 11 versions behind
