Hi Concerning your main question about becoming a crow.
If a MP mission doesn't have a respawn setup and you only have one life then by default you will become a crow when you get killed, a crow basically is another way for you to spectate the game, so basically you become a spectator.
Just a few tips for servers:
1. make sure you have your game patched to the latest before running any mods
2. make sure you can see servers listed in the server browser with your vanilla game before using mods
3. Make sure when you install mods to install them correctly, and that you have the required files for them
4. make sure that you have the server browser set to internet and not lan
This maybe able to help idk:
New to multiplayer? read this guide
Hope that helps.