Ok, I'm making progress, but now I have an entirely new problem.
First, the answer to Number 2 above was located here:
http://forums.cpanel.net/f5/proper-procedure-edit-php-ini-343971.html#post1388731
Basically, I needed to recompile PHP with Safe PHP Cgi turned on.
Now that XCache reads my settings file, I'm getting a different problem. Here are my settings, and the error in the log that loads whenever I try to load a page:
[xcache]
; ini only settings, all the values here is default unless explained
; select low level shm/allocator scheme implemenation
xcache.shm_scheme = "mmap"
xcache.size = 512M
; set to cpu count (cat /proc/cpuinfo |grep -c processor)
xcache.count = 2
xcache.slots = 128K
xcache.ttl = 600
xcache.gc_interval = 600
xcache.var_size = 512M
xcache.var_count = 2
xcache.var_slots = 128K
; default ttl
xcache.var_ttl = 600
xcache.var_maxttl = 7200
;xcache.var_gc_interval = 1800
; for *nix, xcache.mmap_path is a file path, not directory.
; Use something like "/tmp/xcache" if you want to turn on ReadonlyProtection
; 2 group of php won't share the same /tmp/xcache
; for win32, xcache.mmap_path=anonymous map name, not file path
xcache.mmap_path = "/tmp/xcache"
; leave it blank(disabled) or "/tmp/phpcore/"
; make sure it's writable by php (without checking open_basedir)
;xcache.coredump_directory = ""
; per request settings
xcache.cacher = On
xcache.stat = On
xcache.optimizer = On
xcache.test = Off
; N/A for /dev/zero
xcache.readonly_protection = Off
[Wed Dec 11 10:08:17 2013] [notice] Apache/2.2.26 (Unix) mod_ssl/2.2.26 OpenSSL/1.0.1e-fips mod_bwlimited/1.4 mod_fcgid/2.3.6 configured -- resuming normal operations
/tmp/xcache: Permission denied
Cannot open or create file set by xcache.mmap_path, check the path permission or check xcache.size/var_size against system limitation
PHP Fatal error: Cannot open or create file set by xcache.mmap_path, check the path permission or check xcache.size/var_size against system limitation in Unknown on line 0
PHP Fatal error: XCache: Cannot create shm in Unknown on line 0
PHP Fatal error: XCache: Cannot init in Unknown on line 0
It appears to be a problem with the /tmp/xcache folder, but I've checked, and the permissions are 777 and that partition is allowed 2 GB of space, and it's only at 3% now.
Any ideas?