You obviously haven't watched good SFMs.

You can try render the audio file only. SFM is horrible with MP3s. Convert the MP3s in the project to WAVs with Audacity or some other audio editing program.

Alternatively, you can use a video editing software and add the audio manually through there. That's usually what I do.

Promoting yourself is important to let others know of the existance of your work. It's unlikely that people would stumble upon your video by just searching around.

C:

If white lines show up in Hammer as well, click on them and delete them.

https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=232594442

The map needs to be edited and recompiled in SFM Hammer. Portal 2 maps don't work as intended in SFM.

You need at least 2 webcams. Even so, the mocap would be really inaccurate. Recommended would be at least 4.

You really shouldn't look too much into mocap unless you plan on making a studio or you have a lot of fans already and you're experienced in 3D character animation. Mocap is never entirely accurate; quirks will occur, and it will require a bit of experience fixing them up. Only a minor portion of scenes can be mocapped, unless you have the right equipment, which can often be very expensive. Finally, mocap is difficult to set up and use in general, and still considered quite experimental, so it really isn't recommended.

There is Kinect for Windows.

http://www.microsoft.com/en-us/kinectforwindows/

Which map are you trying to load, and how long have you waited for? Maps take a pretty long time to load. If you're on an old computer, expect to wait around a minute or two.