For sleep have you followed the terminal commands and also run the edptool to disable hibernation?
Edptool - option 2 and then option 2. I also did the touch S/L/E, and fix console slow start (options 1 and 3).
http://www.osxlatitude.com/groups/d4xosx/wiki/c1196/Getting_sleep_to_work_on_your_Dell_Latitude_with_OSX.html
http://www.osxlatitude.com/groups/d4xosx/wiki/900e4/How_to_do_a_new_build.html (remember to type in sudo su 1st and then enter your password).
edit: okay went and looked at your bios settings. A few differences mostly because I don't have the modem or Bluetooth. These are how the settings are on mine.
Everything else is the same except for what's listed below.
Integrated NEC – enabled (no pxe)
Internal modem – off
Parallel port – off
Serial port – off
Pcard and 1394 – off
Primary video – onboard video
Password change – denied
Usb wake support – off
Bluetooth – off
Internal cellular – off
Wireless switch - WIFI only
Set them like this and if it works fine then change them 1 by 1 and see where the problem is?