Treating threads as separate states for separate scripts

[Max E <max@...>]

Hello list,

        So I'm trying to have all the scripts in my application run in
separate
lua threads (although none of them are running concurrently.) I wish to
do it this way so I can share a single table between all the scripts.
Besides that, however, I want the scripts to be completely isolated
(with their own global scopes, etc.) I understand the standard way to do
this is to use lua_setfenv to set a table as the environment of a Lua
thread object. What I'm having trouble with is the details. 
        I need all the Lua standard libraries available to each thread,
and I
need each thread to be able to call 'require' on various files, where
sometimes a file might be 'required' on multiple threads. Also, it is
not acceptable for two threads to be able to mess with each others'
global variables by accident. I have tried two methods:
        Method A: create a table with lua_newtable, set it as the
environment
table with lua_setfenv, then call luaL_openlibs on the lua_State I
originally got from lua_newthread. Problem: the standard libraries don't
show up; I don't think luaL_openlibs is doing anything.
        Method B: create a deep copy of the main thread's
LUA_GLOBALSINDEX,
then set that as the environment table. Problem: although the standard
libraries show up just fine now, I can only 'require' a file from one
thread at a time. (And if it's a problem with my deepcopy function, I
freely admit I'm an idiot.)
        If it cannot be done, I can go back to my old system, which was
to have
each script on its own state and use proxies and metamethods to sync up
the shared table, but this wasn't a perfect solution because it was
impossible to 100% emulate a "native" table.

SOURCE CODE:
1) The relevant part of my C code: 
   http://pastebin.com/sRznADVe
2) The entire C file, if you want some context:
   http://pastebin.com/Qp8b72F1
3) The deepcopy function I'm using:
   http://pastebin.com/UfdyfCDF 

I'll provide any other information you want, of course.


Thanks preemptively,
-Max E.