Also the motherboard has a com port on it does that help with the serial interface in anyway?
Not really for the battery controller or the tablet as serial wacom drivers for Windows >7 are virtually nonexistent.
Regarding the battery controller & battery you have the SMBUS lanes (SDA & SCL) somewhere on the motherboard (the 2 pins should also be on each PCIe connector iirc).
It is a bus system so you can connect many different peripherals to the same 2 lines
(each IC has it's own address. Therefore connecting different ICs is no problem but same ICs could be problematic as they have the same address).
In theory this should autodetect your battery controller and show it to the OS via ACPI as laptop battery and it's corresponding controller.