If your eth0 interface is not listed in ip addr output, you may consider blacklisting default r8169 kernel module and installing r8168 as a replacement module.
1) Add blacklist r8169 into /etc/modprobe.d/ethernet.conf:
echo "blacklist r8169" | tee -a /etc/modprobe.d/ethernet.conf
2) Install r8168-dkms from AUR repository
3) If you have r8169 module loaded (lsmod), remove it with rmmod r8169 and load installed r8168 module (modprobe r8168)
Follow Arch Wiki - Bumblebee instructions
Use Xorg configuration files provided here
Blacklist several kernel modules:
> cat /etc/modprobe.d/nvidia.conf
blacklist nvidia
blacklist nouveau
options bbswitch load_state=0