Local recording if you have that. If not I suggest you local record your runs if you stream them and your system can handle it.

You can if your livesplit timer displays the hundredths in the milliseconds (should be like that by default).

Just keep in mind that if you have in game timer turned off, the version wont show in the pie screen and whatnot, which is important for verification. One thing you can do for this is turn on the in game timer in epilogue before showing the pie screen.

You can play music or even have no music. However it's highly advised you have sound effects audible.

Keyboard players use various layouts. Some use the default arrows+zxc while others use WASD for movement and bind their actions around IJKL (or vice versa).

The best is what is most comfortable for you. Controller (d-pad/analog) and keyboard are both viable options.

It's been known for a while. Some people have messed around with it.

You have to go into the autosplitter settings and add the sections where you want it to split. There's some presets for this as well.

You'll have to block the game from the firewall for the ogversion because otherwise it will try to connect to the SQL server which doesn't support the original version anymore.

Here's the post that explains how to fix the issue: https://www.speedrun.com/smb/thread/qmwfs