For starters I am unable to add many multiplayer bipeds.
When I open the tags that come with them in Guerrilla there are spots with red text in them
and as I go through fixing them, some seem to be missing tags in the .zip.

Here's an example:
http://hce.halomaps.org/index.cfm?fid=3629

When I compile it in tool, I get errors.
I noticed that most of the errors come from the energy sword folder.

And yes, I edited the global.globals file.

This is the same problem with some weapon tags as well.

My last problem comes from tiamats C4 tag.
I was able to add it into my map successfully, however, when I go over it.....nothing happens.
It doesn't come into my inventory.

c4 needs the item_collection to work right.
guerrila needs the right directories.
globals.globals needs the exact right amount on the weapon and vehicle pallete, not more, not less.

But I added the item collection and linked it to the c4's .weapon.

As for the other tags, I can't help it if guerrilla shows up with red text, and I try to correct the red text but I can't find the correct tag it's looking for.

Also, I need a better explanation of what you mean on:

You need to change the biped to n_cyborg,or whatever biped timat used in his maps. The original cyborg doesn't have animations for the C4.

I used HEK+ to extract the tags from coldsnap.

I didn't find the biped.
I found the folder: ncyborg though, but all it contained was:
shaders folder
shield.lite file

Try getting this...
http://forum.halomaps.org/index.cfm%3Fpage=topic&topicID=30944
It has all the standard bipeds.