How is your physics model rigged to your armature?

Oh, I see. You have to specifically select a number of objects and export them as a small group.

Now that I can also make Blender crash, I will investigate.

Using Blender 3.3.1, I could export every model in the scene at the same time without any issues. Perhaps you have some other addon installed which is causing issues?

Please send me the blend file you are exporting, and I'll try to reproduce this crash.

You have to create shape keys in Blender. These will be exported as flexes. If you are exporting SMD you will also have to set them up in the QC file.

You'll find lots of documentation for both of these things online.

It's a bug in that version of Blender. Upgrade it and the Source Tools.

Yes.

You can use Blender's built-in text editor. The Tools will generate a Text when you click on the button mentioned in the documentation.

You need to use advanced flex mode and edit your flex controller DMX element.

https://developer.valvesoftware.com/wiki/Blender_Source_Tools_Help#Advanced_mode

Each animation was imported as an Action, but Blender will only display one action at a time.

I added a small UI element to the Tools interface to help you switch between actions.